1

Final Environmental Assessment Rangeland Grasshopper 

and Mormon Cricket Suppression Program

Elko, Eureka, and Lander Counties, Nevada

EA Number: NV-04-20

Prepared by:

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

8775 Technology Way

Reno, NV 89521

May 27, 2020
2

Table of Contents

I. Need for Proposed Action...................................................................................................... 5

A. Purpose and Need Statement .............................................................................................. 5

B. Background Discussion ...................................................................................................... 5

C. About This Process............................................................................................................. 8

II. Alternatives............................................................................................................................ 8

A. No Action Alternative....................................................................................................... 10

B. Insecticide Applications at Conventional Rates or Reduced Agent Area Treatments with 

Adaptive Management Strategy (Preferred Alternative)........................................................ 10

III. Affected Environment.......................................................................................................... 11

A. Description of Affected Environment............................................................................... 11

B. Site-Specific Considerations............................................................................................. 12

1. Human Health ................................................................................................................ 12

2. Non-target Species......................................................................................................... 13

a) Migratory Birds....................................................................................................... 13

b) Endangered Species................................................................................................ 13

c) Bald and Golden Eagles.......................................................................................... 13

d) Additional Species of Concern ............................................................................... 14

3. Socioeconomic Issues.................................................................................................... 14

4. Cultural Resources and Events ...................................................................................... 15

5. Special Considerations for Certain Populations ............................................................ 17

a) Executive Order No. 12898, Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations........................................................ 17

b) Executive Order No. 13045, Protection of Children from Environmental Health 

Risks and Safety Risks...................................................................................................... 17

IV. Environmental Consequences.............................................................................................. 18

A. Environmental Consequences of the Alternatives............................................................ 18

1. No Action Alternative.................................................................................................... 18

2. Insecticide Applications at Conventional Rates or Reduced Agent Area Treatments 

with Adaptive Management Strategy.................................................................................... 19

a) Carbaryl................................................................................................................... 19

b) Diflubenzuron ......................................................................................................... 22

c) Malathion ................................................................................................................ 25

d) Reduced Area Agent Treatments (RAATs)............................................................ 27

B. Other Environmental Considerations................................................................................ 29

1. Cumulative Impacts....................................................................................................... 29

2. Executive Order No. 12898, Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations............................................................ 30

3. Executive Order No. 13045, Protection of Children from Environmental Health Risks 

and Safety Risks.................................................................................................................... 31

4. Tribal Consultation ........................................................................................................ 32

5. Executive Order 13186, Responsibilities of Federal Agencies to Protect Migratory 

Birds...................................................................................................................................... 33

6. Endangered Species Act ................................................................................................ 33
3

7. Bald and Golden Eagle Protection Act .......................................................................... 35

8. Additional Species of Concern ...................................................................................... 35

9. Fires and Human Health Hazards.................................................................................. 36

10. Cultural and Historical Resources ................................................................................. 37

V. Literature Cited .................................................................................................................... 37

VI. Listing of Agencies and Persons Consulted......................................................................... 47

Appendix A................................................................................................................................... 48

APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program........................ 48

General Guidelines for Grasshopper / Mormon Cricket Treatments...................................... 48

Operational Procedures........................................................................................................... 49

GENERAL PROCEDURES FOR ALL AERIAL AND GROUND APPLICATIONS ...... 49

SPECIFIC PROCEDURES FOR AERIAL APPLICATIONS............................................. 50

Appendix B................................................................................................................................... 52

2019 Grasshopper Survey Cumulative ................................................................................... 52

2019 Mormon Cricket Survey Cumulative............................................................................. 53

Appendix C Table 1...................................................................................................................... 54

Endangered Species Act Species............................................................................................ 56

Mammals............................................................................................................................... 56

Fishes .................................................................................................................................... 56

Conifers and Cycads............................................................................................................. 57

Critical habitats....................................................................................................................... 57

USFWS National Wildlife Refuge Lands AndFish Hatcheries.............................................. 58

Migratory Birds....................................................................................................................... 59

Appendix C Table 2...................................................................................................................... 62

Part I........................................................................................................................................ 62

Part II ...................................................................................................................................... 77

Appendix C Table 3...................................................................................................................... 79

Appendix D....................................................................................Error! Bookmark not defined.

APHIS response to public comments on the Nevada Draft EAs........... Error! Bookmark not 

defined.
4

Appendices

Appendix A: FY 2020 Guidelines for Treatment of Rangeland for the 

Suppression of Grasshoppers and Mormon Crickets, USDA APHIS PPQ 

Western Region ...............................................................................................48

Appendix B: Map of Affected Environment .......................................................52

Appendix C: FWS/NMFS Correspondence ........................................................54

Appendix D: APHIS response to public comments on the Nevada Draft EAs...82

Non-Discrimination Policy 

The U.S. Department of Agriculture (USDA) prohibits discrimination against its customers, employees, and applicants for employment on the 

bases of race, color, national origin, age, disability, sex, gender identity, religion, reprisal, and where applicable, political beliefs, marital status, 

familial or parental status, sexual orientation, or all or part of an individual's income is derived from any public assistance program, or protected 

genetic information in employment or in any program or activity conducted or funded by the Department. (Not all prohibited bases will apply to 

all programs and/or employment activities.) 

To File an Employment Complaint 

If you wish to file an employment complaint, you must contact your agency's EEO Counselor (PDF) within 45 days of the date of the alleged 

discriminatory act, event, or in the case of a personnel action. Additional information can be found online at 

http://www.ascr.usda.gov/complaint_filing_file.html. 

To File a Program Complaint 

If you wish to file a Civil Rights program complaint of discrimination, complete the USDA Program Discrimination Complaint Form (PDF), 

found online at http://www.ascr.usda.gov/complaint_filing_cust.html, or at any USDA office, or call (866) 632-9992 to request the form. You 

may also write a letter containing all of the information requested in the form. Send your completed complaint form or letter to us by mail at U.S. 

Department of Agriculture, Director, Office of Adjudication, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, by fax (202) 

690-7442 or email at program.intake@usda.gov. 

Persons With Disabilities 

Individuals who are deaf, hard of hearing, or have speech disabilities and you wish to file either an EEO or program complaint please contact 

USDA through the Federal Relay Service at (800) 877-8339 or (800) 845-6136 (in Spanish). 

Persons with disabilities who wish to file a program complaint, please see information above on how to contact us by mail directly or by email. If 

you require alternative means of communication for program information (e.g., Braille, large print, audiotape, etc.) please contact USDA's 

TARGET Center at (202) 720-2600 (voice and TDD). 

Mention of companies or commercial products in this report does not imply recommendation or endorsement by USDA over others not 

mentioned. USDA neither guarantees nor warrants the standard of any product mentioned. Product names are mentioned to report factually on 

available data and to provide specific information.

This publication reports research involving pesticides. All uses of pesticides must be registered by appropriate State and/or Federal agencies 

before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish and other wildlife—if they are not handled or 

applied properly. Use all pesticides selectively and carefully. Follow recommended label practices for the use and disposal of pesticides and 

pesticide containers
5

Final Site-Specific Environmental Assessment 

Rangeland Grasshopper and Mormon Cricket Suppression Program

Elko, Eureka, and Lander Counties, Nevada

I. Need for Proposed Action

A. Purpose and Need Statement

An infestation of grasshoppers or Mormon crickets may occur in Nevada, specifically

Elko, Eureka, and Lander counties. The Animal and Plant Health Inspection Service 

(APHIS) and Nevada Department of Agriculture (NDA) may, upon request by land 

managers or State departments of agriculture, conduct treatments to suppress grasshopper 

infestations as part of the Rangeland Grasshopper and Mormon Cricket Suppression 

Program (program). The term “grasshopper” used in this environmental assessment (EA) 

refers to both grasshoppers and Mormon crickets, unless differentiation is necessary.

Populations of grasshoppers that trigger the need for a suppression program are normally 

considered on a case-by-case basis. Participation is based on potential damage such as 

stressing and/or causing the mortality of native and planted range plants or adjacent crops 

due to the feeding habits of large numbers of grasshoppers. The benefits of treatments 

including the suppressing of over abundant grasshopper populations to lower adverse 

impacts to range plants and adjacent crops. Such would decrease the economic impact to 

local agricultural operations and permit normal range plant utilization by wildlife and 

livestock. Some populations that may not cause substantial damage to native rangeland 

may require treatment due to the secondary suppression benefits resulting from the high 

value of adjacent crops and damage to revegetation programs. The goal of the proposed 

suppression program analyzed in this EA is to reduce grasshopper populations to 

economically acceptable levels in order to protect rangeland ecosystems or cropland 

adjacent to rangeland.

This EA analyzes potential effects of the proposed action and its alternatives. This EA 

applies to a proposed suppression program that would take place from April to September

in Elko, Eureka, and Lander counties. 

This EA is prepared in accordance with the requirements under the National 

Environmental Policy Act of 1969 (NEPA) (42 United States Code § 4321 et. seq.) and 

the NEPA procedural requirements promulgated by the Council on Environmental 

Quality, United States Department of Agriculture (USDA), and APHIS. A decision will 

be made by APHIS based on the analysis presented in this EA, the results of public 

involvement, and consultation with other agencies and individuals. A selection of one of 

the program alternatives will be made by APHIS for the 2020 Control Program for Elko, 

Eureka, and Lander counties.

B. Background Discussion

Rangelands provide many goods and services, including food, fiber, recreational 

opportunities, and grazing land for cattle (Havstad et al., 2007; Follett and Reed, 2010). 
6

Grasshoppers and Mormon crickets are part of rangeland ecosystems, serving as food for 

wildlife and playing an important role in nutrient cycling. However, grasshoppers and 

Mormon crickets have the potential to occur at high population levels (Belovsky et al., 

1996),that result in competition with livestock and other herbivores for rangeland forage 

and can result in damage to rangeland plant species.

In rangeland ecosystem areas of the United States, grasshopper populations can build up 

to economic infestation levels1 despite even the best land management and other efforts 

to prevent outbreaks. At such a time, a rapid and effective response may be requested and 

needed to reduce the destruction of rangeland vegetation. In some cases, a response is 

needed to prevent grasshopper migration to cropland adjacent to rangeland. 

APHIS surveys grasshopper populations on rangeland in the Western United States, 

provides technical assistance on grasshopper management to land owners and managers, 

and may cooperatively suppress grasshoppers when direct intervention is requested by a 

Federal land management agency or a State agriculture department (on behalf of a State 

or local government, or a private group or individual). APHIS’ enabling legislation 

provides, in relevant part, that ‘on request of the administering agency or the agriculture 

department of an affected State, the Secretary, to protect rangeland, shall immediately 

treat Federal, State, or private lands that are infested with grasshoppers or Mormon 

crickets’... (7 U.S.C. § 7717(c)(1)). The need for rapid and effective response when an 

outbreak occurs limits the options available to APHIS. The application of an insecticide 

within all or part of the outbreak area is the response available to APHIS to rapidly 

suppress or reduce grasshopper populations and effectively protect rangeland. 

In June 2002, APHIS completed an Environmental Impact Statement (EIS) document 

concerning suppression of grasshopper populations in 17 Western States (Rangeland 

Grasshopper and Mormon Cricket Suppression Program, Environmental Impact 

Statement, June 21, 2002). The EIS described the actions available to APHIS to reduce 

the damage caused by grasshopper populations in Arizona, California, Colorado, Idaho, 

Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, 

South Dakota, Texas, Utah, Washington, and Wyoming. During November 2019, APHIS 

published an updated EIS to incorporate the available data and analyze the environmental 

risk of new program tools. 

Nevada Revised Statutes 561.245 provides authority to cooperate with and enter into 

contracts or agreements with the Federal government. Nevada Revised Statutes 555.2605 

– 555.470 are laws on the custom application of pesticides and restricted use pesticides. 

 1 The “economic infestation level” is a measurement of the economic losses caused by a particular population level 

of grasshoppers to the infested rangeland. This value is determined on a case-by-case basis with knowledge of many 

factors including, but not limited to, the following: economic use of available forage or crops; grasshopper species, 

age, and density present; rangeland productivity and composition; accessibility and cost of alternative forage; and 

weather patterns. In decision making, the level of economic infestation is balanced against the cost of treating to 

determine an “economic threshold” below which there would not be an overall benefit for the treatment. Short-term 

economic benefits accrue during the years of treatments, but additional long-term benefit may accrue and be 

considered in deciding the total value gained by treatment. Additional losses to rangeland habitat and cultural and 

personal values (e.g., aesthetics and cultural resources), although a part of decision making, are not part of the 

economic values in determining the necessity of treatment.
7

These contain the requirements for a license to apply pesticides and certification to use 

and sell restricted use pesticides.

In October 2015, APHIS and the Bureau of Land management (BLM) signed a 

Memorandum of Understanding (MOU) detailing cooperative efforts between the two 

groups on the suppression of grasshoppers on BLM system lands (Document # 15-8100-

0870-MU, October 15, 2015). This MOU clarifies that APHIS would prepare and issue 

to the public site-specific environmental documents that evaluate potential impacts 

associated with proposed measures to suppress economically damaging grasshopper 

populations. The MOU also states that these documents would be prepared under the 

APHIS NEPA implementing procedures with cooperation and input from BLM.

The MOU further states that the responsible BLM official would request in writing the 

inclusion of appropriate lands in the APHIS suppression project when treatment on BLM 

land is necessary. The BLM must also prepare a Pesticide Use Proposal for APHIS to 

treat infestations. According to the provisions of the MOU, APHIS can begin treatments 

after APHIS issues an appropriate decision document and BLM prepares and approves 

the Pesticide Use Proposal.

In September 2016, APHIS and the Bureau of Indian Affairs (BIA) signed a 

Memorandum of Understanding (MOU) detailing cooperative efforts between the two 

groups on the suppression of grasshoppers on BIA system lands. This MOU clarifies that 

APHIS would prepare and issue to the public site-specific environmental documents that 

evaluate potential impacts associated with the proposed measures to suppress 

economically damaging grasshopper populations. The MOU also states that these 

documents would be prepared under the APHIS NEPA implementation procedures with 

cooperation and input from the BIA. 

The MOU further states that the responsible BIA official would request in writing the 

inclusion of appropriate lands in the APHIS suppression project when treatment on BIA 

land is necessary The BIA must also prepare a Pesticide Use Proposal for APHIS to treat 

infestations. According to the provisions of the MOU, APHIS can begin treatments after 

APHIS issues an appropriate decision document and BIA prepares and approves the 

Pesticide Use Proposal.

In November 2019, APHIS and the Forest Service (FS) signed a Memorandum of 

Understanding (MOU) detailing cooperative efforts between the two groups on the 

suppression of grasshoppers on FS system lands (Document # 19-8100-0573-MU, 

November 06, 2019). This MOU clarifies that APHIS would prepare and issue to the 

public site-specific environmental documentations that evaluate potential impacts 

associated with the proposed measures to suppress economically damaging grasshopper 

populations. The MOU also states that these documents would be prepared under the 

APHIS NEPA implementation procedures with cooperation and input from the FS. 

The MOU further states that the responsible FS official would request in writing the 

inclusion of appropriate lands in the APHIS suppression project when treatment on FS 

land is necessary The FS must also prepare a Pesticide Use Proposal (Form: FS-2100-2) 
8

for APHIS to treat infestations. According to the provisions of the MOU, APHIS can 

begin treatments after APHIS issues an appropriate decision document and FS prepares 

and approves the Pesticide Use Proposal.

C. About This Process

The EA process for grasshopper management is complicated by the fact that there is very 

little time between requests for treatment and the need for APHIS to take action with 

respect to those requests. Surveys help to determine general areas, among the scores of 

millions of acres that potentially could be affected, where grasshopper infestations may 

occur in the spring of the following year. Survey data provides the best estimate of future 

grasshopper populations, yet environmental factors lead to certain forecasts where the

specific treatment areas will be. Therefore examining specific treatment areas for 

environmental risk analysis under NEPA is typically not possible. At the same time, the 

program strives to alert the public in a timely manner to its more concrete treatment plans 

and avoid or minimize harm to the environment in implementing those plans.

The current EIS provides a solid analytical foundation; however, it may not be enough to 

satisfy NEPA completely for actual treatment proposals. The program typically prepares

a Draft EA tiered to the current EIS for each of the 17 Western States, or portion(s) of a 

state, that may receive a request for treatment. The Draft EA analyzes aspects of 

environmental quality that could be affected by treatments in the area where grasshopper 

outbreaks are anticipated. The Draft EA will be made available to the public for a 30-day 

comment period. When the program receives a treatment request and determines that 

treatment is necessary, the specific site within the state will be evaluated to determine if 

environmental factors were thoroughly evaluated in the Draft EA. If all environmental 

issues were accounted for in the Draft EA, the program will prepare a Final EA and 

Finding of No Significant Impact (FONSI). Once the FONSI has been finalized copies of 

those documents will be sent to any parties that submitted comments on the Draft EA,

and to other appropriate stakeholders. To allow the program to respond to comments in a 

timely manner, the Final EA and FONSI will be posted to the APHIS website. The 

program will also publish a notice of availability in the same manner used to advertise the 

availability of the Draft EA.

II. Alternatives

To engage in comprehensive NEPA risk analysis APHIS must frame potential agency 

decisions into distinct alternative actions. These program alternatives are then evaluated 

to determine the significance of environmental effects. The 2002 EIS presented three 

alternatives: (A) No Action; (B) Insecticide Applications at Conventional Rates and 

Complete Area Coverage; and (C) Reduced Agent Area Treatments (RAATs), and their 

potential impacts were described and analyzed in detail. The 2019 EIS was tiered to, and 

updated the 2002 EIS. Therefore the 2019 EIS considered the environmental background 

or ‘No Action’ alternative of maintaining the program that was described in the 2002 EIS 

and Record of Decision. The 2019 EIS also considered an alternative where APHIS 

would not fund or participate in grasshopper suppression programs. The preferred 

alternative of the 2019 EIS allowed APHIS to update the program with new information 

and technologies that not were analyzed in the 2002 EIS. Copies of the complete 2002 
9

and 2019 EIS documents are available for review at 8775 Technology Way, Reno, NV 

89521. These documents are also available at the Rangeland Grasshopper and Mormon 

Cricket Program web site, http://www.aphis.usda.gov/plant-health/grasshopper. 

All insecticides used by APHIS for grasshopper suppression are used in accordance with 

applicable product label instructions and restrictions. Representative product specimen 

labels can be accessed at the Crop Data Management Systems, Inc. web site at 

www.cdms.net/manuf/manuf.asp. Labels for actual products used in suppression 

programs will vary, depending on supply issues. All insecticide treatments conducted by 

APHIS will be implemented in accordance with APHIS’ treatment guidelines and 

operational procedures, included as Appendix A to this Final EA. 

APHIS technical guidance is part of each alternative proposed, and is not unique to any 

one alternative. An example of APHIS technical guidance is the agency’s work on 

integrated pest management (IPM) for the grasshopper program. IPM for grasshoppers 

includes biological control, chemical control, rangeland and population dynamics, and 

decision support tools.

APHIS has funded the investigation of various integrated pest management (IPM) 

strategies for the grasshopper program. Congress established the Grasshopper Integrated 

Pest Management (GIPM) to study the feasibility of using IPM for managing 

grasshoppers.

The major objectives of the APHIS GIPM program were to: 1) manage grasshopper 

populations in study areas, 2) compare the effectiveness of an IPM program for rangeland 

grasshoppers with the effectiveness of a standard chemical control program on a regional 

scale, 3) determine the effectiveness of early sampling in detecting developing 

grasshopper infestations, 4) quantify short- and long-term responses of grasshopper 

populations to treatments, and 5) develop and evaluate new grasshopper suppression 

techniques that have minimal effects on non-target species (Quinn, 2000).

Federal and State land management agencies, State agriculture departments, and private 

groups or individuals may carry out a variety of preventative IPM strategies that may 

reduce the potential for grasshopper outbreaks. Some of these activities include grazing 

management practices, cultural and mechanical methods, and prescribe-burning of 

rangeland areas. These techniques have been tried with varying success in rangeland 

management, and some have been associated with the prevention, control, or suppression 

of harmful grasshopper populations on rangeland.

Regardless of the various IPM strategies taken, the primary focus of the risk analysis 

contained in this EA is on the potential impacts from chemical treatments needed during 

an outbreak of economic importance. While APHIS provides technical expertise 

regarding grasshopper management actions, the responsibility for implementing most 

land management practices lies with other Federal (i.e., BIA, BLM, and USDA’s FS), 

State, and private land managers.
10

This Final EA analyzes the significance of environmental effects that could result from 

the alternatives described below. These alternatives differ from those described in the 

2019 EIS because grasshopper treatments are not likely to occur in most of Elko, Eureka, 

and Lander counties, and therefore the environmental baseline should describe a no 

treatment scenario. 

A. No Action Alternative

Under Alternative A, the No Action alternative, APHIS would not conduct a program to 

suppress grasshopper infestations within Elko, Eureka, and Lander counties. Under this

alternative, APHIS may opt to provide limited technical assistance, but any suppression 

program would be implemented by a Federal land management agency, a State 

agriculture department, a local government, or a private group or individual.

B. Insecticide Applications at Conventional Rates or Reduced Agent 

Area Treatments with Adaptive Management Strategy (Preferred 

Alternative)

Under Alternative B, the Preferred Alternative, APHIS would manage a grasshopper 

treatment program using techniques and tools discussed hereafter to suppress outbreaks. 

The insecticides available for use by APHIS include the U.S. Environmental Protection 

Agency (USEPA) registered chemicals carbaryl, diflubenzuron, and malation. These 

chemicals have varied modes of action: carbaryl and malathion work by inhibiting 

acetylcholinesterase (enzymes involved in nerve impulses) while diflubenzuron is a chitin 

inhibitor. APHIS would make a single application per year to a treatment area, and could 

apply insecticide at an APHIS rate conventionally used for grasshopper suppression 

treatments, or more typically as reduced agent area treatments (RAATs). APHIS selects 

which insecticides and rates are appropriate for suppression of a grasshopper outbreak 

based on several biological, logistical, environmental, and economical criteria. The 

identification of grasshopper species and their life stage largely determines the choice of 

insecticides used among those available to the program. RAATs are the most common 

application method for all program insecticides, and only rarely do rangeland pest 

conditions warrant full coverage and higher rates.

The RAATs strategy is effective for grasshopper suppression because the insecticide 

controls grasshoppers within treated swaths while conserving grasshopper predators and 

parasites in swaths not directly treated. RAATs can decrease the rate of insecticide 

applied by either using lower insecticide concentrations or, more commonly, decreasing 

the deposition of insecticide applied by alternating one or more treatment swaths. Both 

options could potentially be incorporated simultaneously into RAATs. Based on the total 

percent coverage of a treatment area, either carbaryl, diflubenzuron, or malathion could

be considered under this alternative at the following application rates:

• 8.0-16.0 fluid ounces (0.25-0.50 lb a.i.) of carbaryl ULV spray per acre;

• 2.0-10.0 pounds (0.04-0.20 lb a.i.) of 2 percent carbaryl bait per acre;

• 2.0-10.0 pounds (0.10-0.50 lb a.i.) of 5 percent carbaryl bait per acre;

• 0.75 or 1.0 fluid ounce (0.012-0.016 lb a.i.) of diflubenzuron per acre; or

• 4.0-8.0 fluid ounces (0.31-0.62 lb a.i.) of malathion per acre.
11

The width of the area not directly treated (the untreated swath) under the RAATs

approach is not standardized. The proportion of land treated in a RAATs approach is a 

complex function of the rate of grasshopper movement, which is a function of 

developmental stage, population density, and weather (Narisu et al., 1999, 2000), as well 

as the properties of the insecticide (insecticides with longer residuals allow wider spacing 

between treated swaths). Foster et al. (2000) left 20 to 50% of their study plots untreated, 

while Lockwood et al. (2000) left 20 to 67% of their treatment areas untreated. Currently 

the grasshopper program typically leaves 50% of a spray block untreated for ground 

applications where the swath width is between 20 and 45 feet. For aerial applications, the 

skipped swath width is typically no more than 20 feet for malathion, 100 feet for carbaryl 

and 200 feet for diflubenzuron. The selection of insecticide and the use of an associated 

swath widths is site dependent. Rather than suppress grasshopper populations to the 

greatest extent possible, the goal of this alternative is to suppress grasshopper populations 

to a desired level. 

Insecticide applications at conventional rates and complete area coverage, is an approach 

that APHIS has used in the past but is currently uncommon. Under this alternative, 

carbaryl, diflubenzuron, or malathion would cover all treatable sites within the designated 

treatment block per label directions. The application rates under this alternative are as 

follows:

• 16.0 fluid ounces (0.50 pound active ingredient (lb a.i.)) of carbaryl spray per 

acre;

• 10.0 pounds (0.20 lb a.i.) of 2 percent carbaryl bait per acre;

• 10.0 pounds (0.50 lb a.i.) of 5 percent carbaryl bait per acre;

• 1.0 fluid ounce (0.016 lb a.i.) of diflubenzuron per acre; or

• 8.0 fluid ounces (0.62 lb a.i.) of malathion per acre.

The potential generalized environmental effects of the application of carbaryl, 

diflubenzuron, and malathion, under this alternative are discussed in detail in the 2019 

EIS. A description of anticipated site-specific impacts from this alternative may be found 

in Part IV of this document.

III. Affected Environment

A. Description of Affected Environment

The proposed suppression program area included in the EA encompasses 17,183,360

acres (26,849 sq. mi.) within northern Nevada. Approximately 85% of the land area is 

classified as Federal with the remainder State and private lands. Most of the area is high 

desert and mountain country. The lowest elevation is approximately 4,000 feet and 

11,000 feet at its highest. A map of the program suppression area is attached hereto as 

Appendix B. The actual program area that may be treated will be determined by surveys 

done in early spring. 
12

The area is semi-arid and the majority of precipitation falls from October to June, as a 

result of Pacific storms. The precipitation varies from 4 inches a year in the valleys to 

over 20 inches a year in the mountains. Normally, the area is snow free from June to 

October, but snow can occur at any time. The soils are in climatic groups including

desert, semi desert, upland mountain and high mountain with some irrigated soils. 

Agriculture areas include native and improved rangeland, pasture and cropland. 

Treatment guidelines in Appendix A would be followed to provide the least effect on 

soils.

Major waterways include, but are not limited to: Humboldt River, South Fork of the 

Humboldt River, North Fork of the Humboldt River, Fall Creek, Bruneau River, Owyhee 

River, South Fork of the Owyhee River, Reese River, Jarbidge River, Pearl Creek, 

Lamoille Creek, Thorpe Creek, Gold Creek, Pole Creek, Soldier Creek, Secret Creek, 

Leach Creek, Boulder Creek, Goose Creek, Jakes Creek, Sun Creek, Camp Creek, 

Cottonwood Creek, Canyon Creek, McDonald Creek, Telephone Creek, Beaver Creek, 

Badger Creek, Pratt Creek, Columbia Creek, Jacks Creek, Rock Creek, Toe Jam Creek, 

Trout Creek, Mill Creek, Willow Creek, Roberts Creek, Skull Creek, Stoneburger Creek, 

Birch Creek, Kingston Creek, Smith Creek, and Fish Creek. In addition, there are other 

important smaller streams. Lakes, reservoirs and playas include: South Fork Reservoir, 

Wild Horse Reservoir, Wilson Sink Reservoir, Saval Reservoir, Sheep Creek Reservoir, 

Metropolis Reservoir, Crittenden Reservoir, Dake Reservoir, Jakes Creek Reservoir, 

Dorsey Reservoir, Chimney Creek Reservoir, Ruby Lake, and Willow Creek Reservoir. 

Recreation activities vary considerably throughout the area. Primary activities include 

hunting, fishing, off-road vehicle use, hiking, backpacking, rockhounding and horseback 

riding. Related uses are camping, sightseeing, photography and nature study. Overall, 

primary use is low except in developed recreation sites and along major reservoirs. 

Major recreational areas in this Region include: Mill Creek, Hickson Petroglyph Area, 

South Fork Reservoir, Ruby Lake, Wild Horse Reservoir, Wilson Sink Reservoir, Saval 

Reservoir, Sheep Creek Reservoir, Zunio Reservoir, and the Ruby Mountains. The water 

resources provide water for wildlife, wild horses/burros, and domestic livestock use as 

well as habitat for wildlife. 

Portions of the Humboldt-Toiyabe National Forest is also within the assessment area and 

the Ruby Lake National Wildlife Refuge is located in Elko County, Nevada. BLM lands 

in the project area are administered by Battle Mountain and Elko field offices.

The principle rangeland vegetation in the area is: Bitterbrush, Big Sagebrush, Indian 

ricegrass, Winterfat, Greasewood, Horsebrush, Rabbitbrush, Paintbrush, Perennial 

bunchgrasses, and Blue grasses.

B. Site-Specific Considerations

1. Human Health

Population centers within the district include the towns of Austin, Battle Mountain, 

Carlin, Elko, Eureka, jackpot, Midas, Montello, Mountain City, Owyhee, Tuscarora, 
13

Wells, and Wendover. No ULV aerial applications of malathion, carbaryl, or 

diflubenzuron would be conducted over these congested areas. The major schools are 

located within the city limits of these towns. The approximate population of the three

counties is approximately 60,300 (U.S. Census Bureau, March 2018). 

Indian Reservations/colonies that are within the boundaries of the assessment area 

include: Duck Valley Indian Reservation, South Fork Indian Reservation, Odgers Ranch 

Indian Reservation, Ruby Valley Allotment, Battle Mountain Indian Colony, and Elko 

Indian Colony.

Potential exposures to the general public from traditional application rates are infrequent 

and of low magnitude. Program use of carbaryl, malathion and diflubenzuron has 

occurred routinely in many past programs, and there is a lack of any adverse health 

effects reported from these projects. Therefore, routine safety precautions as listed on 

chemical labels would continue to provide adequate protection of worker health. 

Immunotoxic effects from carbaryl and malathion exposure are generally expected at 

concentrations much higher than those from grasshopper applications, but individuals 

with allergic or hypersensitive reactions to the insecticides or other chemicals in the 

formulated product could be affected. These individuals would be advised to avoid 

treatment areas at the time of application until the insecticides has time to dry on the 

treated vegetation. 

2. Non-target Species

Proposed treatment areas have been tentatively identified in Northern Nevada. There are 

species of concern in some of the treatment blocks. Should other areas warrant treatment, 

the local land managers will be consulted. 

a) Migratory Birds

The U.S. Fish and Wildlife Service (USFWS) list of migratory bird species in Nevada is 

attached (Appendix C – Table 1). Migratory bird species of concern will be addressed 

through local consultation with land managers and USFWS. 

b) Endangered Species

The U.S. Fish and Wildlife Service (USFWS) list of endangered, threatened, candidate 

and proposed species of concern in Nevada is attached (Appendix C – Table 1).

Species for Federal listing state-listed species, and/or other sensitive species identified by 

state or federal agencies within the area include: Columbia Spotted frog, Greater sagegrouse, Yellow-Billed Cuckoo, Bald Eagle, Desert dace, Lahontan and Paiute cutthroat 

trout, Warner sucker, cui-ui, Carson wandering skipper, Steamboat buckwheat and Weber 

Ivesia. 

c) Bald and Golden Eagles

Bald and golden eagles are known to occur in the proposed treatment areas. Bald and 

golden eagle populations and their nesting sites will be identified prior to treatment 

through local consultation with land managers and USFWS.
14

d) Additional Species of Concern 

Game species known to occur within the general areas proposed for spraying include 

Bighorn sheep, mule deer, pronghorn antelope, mountain lion, cottontail rabbit mourning 

dove, sage grouse, chucker, Hungarian partridge and several species of waterfowl. A 

number of cold and warm water game fish occur in the various lakes, streams and 

reservoirs in the area. Wild horses and burros are managed by the BLM on numerous 

herd management areas throughout the proposed suppression program area. It is 

anticipated that aerial control programs will not be in areas where populations of wild 

horses/burros are found. 

A diversity of non-game wildlife occurs in the area (birds, reptiles, amphibians, and 

mammals) including wild horses. The greatest abundance and diversity of most species 

occurs in riparian and wetland habitat types. 

3. Socioeconomic Issues

Recreation use is moderate over most of the affected area. There are several dispersed 

camping sites. Hunting seasons increase recreation use in the form of dispersed camping 

and general hunting activity. Hunting season occurs later in the year during a time when 

grasshopper populations have begun to dwindle, thus fewer are present. Hunters 

probably would not be affected. ATV use is fairly prevalent throughout. The presence of 

high densities of grasshoppers would result in fewer people engaging in recreational 

activities during the spring and summer within the affected areas. High grasshopper 

densities in the campsite detract considerably from the quality of the recreational 

experience. Grasshoppers tend to get into unsecured tents and food. The quality of the 

recreational experience for ATV users and horseback riders would also be indirectly 

impaired by high densities of grasshoppers. Large quantities of grasshoppers crossing 

roads and trails are killed by vehicle traffic, leaving windrows of dead grasshoppers in 

the travel way as well as providing a vehicular safety hazard by leaving slick residues on 

local roads. People who normally recreate in areas that are heavily infested would likely 

relocate them to areas that are not infested. Displacement of users would be more of an 

inconvenience to the public than an actual effect on the recreational values of the area. 

Displacement would also increase pressure on other public lands as people move to new 

locations to camp and to engage in other recreational activities. Social capacity 

tolerances would be impacted. The potential for user conflict would increase, in 

particular as motorized recreationists displace to other already heavily used areas. Such 

locations would experience more pressure and may experience site degradation. Areas 

currently not impacted or used by dispersed campers may become subject to use and 

development as people look for areas for recreation which are not infested with 

grasshoppers. Small towns near the affected areas receive limited business from 

recreationists who visit public lands. Many local gas stations/public stores rely fairly 

heavily on summer business to support their operations. 

Livestock grazing is one of the main uses of most of the affected area, which provides 

summer range for ranching operations. Permittees may run cattle, sheep and/or horses 

for a season that runs generally from the first of June to the end of September, weather 

and vegetation conditions permitting. 
15

A substantial threat to the animal productivity of these rangeland areas is the proliferation 

of grasshopper populations. These insects have been serious pests in the Western States 

since early settlement. Weather conditions favoring the hatching and survival of large 

numbers of grasshoppers can cause outbreak populations, resulting in damage to 

vegetation. The consequences may reduce grazing for livestock and result in loss of food 

and habitat for wildlife. Livestock grazing on public lands contributes important cultural 

and social values to the area. Intertwined with the economic aspects of livestock 

operations are the lifestyles and culture that have co-evolved with Western ranching. 

Rural and social values and lifestyles, in conjunction with the long heritage of ranching 

and farming continue to this day, dating back to the earliest pioneers in Nevada, who 

shaped the communities and enterprises that make up much of Nevada. The rural 

Western lifestyle also contributes to tourism in the area, presenting to travelers a flavor of 

the west through tourist-oriented goods and services, photography of sheep bands or 

cattle in pastoral settings and scheduled events. 

Ranchers displaced from public lands due to early loss of forage from grasshopper 

damage would be forced to search for other rangeland, to sell their livestock prematurely 

or to purchase feed hay. This would affect other ranchers (non-permittees) by increasing 

demand, and consequently, cost for hay and/or pasture in the area. This would have a 

beneficial effect on those providing the hay or range, and a negative impact on other 

ranchers who use these same resources throughout the area. In addition, grazing on 

private lands resulting from this impact would compound the effects to vegetation of 

recently drought conditions over the last four fears (e.g.., continual heavy utilization by 

grasshoppers, wildlife and wildfire), resulting in longer-term impacts (e.g., decline or loss 

of some preferred forage species) on grazing forage production on these lands. The lack 

of treatment would result in the eventual magnification of grasshopper problems resulting 

in increased suppression efforts, increased suppression costs and the expansion of 

suppression needs onto lands where such operations are limited. For example, control 

needs on crop lands where chemical options are restricted because of pesticide label 

restrictions. Under the no action alternative, farmers would experience economic losses. 

The suppression of grasshoppers in the affected area would have beneficial economic 

impacts to local landowners, farmers, and beekeepers. Crops near infested lands would 

be protected from devastating migrating hordes, resulting in higher crop production; 

hence, increased monetary returns.

4. Cultural Resources and Events

Federal and public lands that are part of the Region’s visual and cultural resources 

include the Humboldt-Toiyabe National Forest, Ruby Lake National Wildlife Refuge, 

Goshute Wildlife Area, East Humboldt Wilderness Area, Ruby Mountain Wilderness 

Area, Jarbridge Wilderness Area, Hickson Petroglyph State Park, Wild Horse State Park, 

and South Fork Reservoir State Park. The South Ruby Marsh is located in Elko County.

A broad variety and number of activities have occurred, are occurring or would occur 

throughout the area of concern that affects cultural resources. These activities and any 
16

cumulative impacts associated with them would occur regardless of whether or not 

grasshoppers are treated.

Use of motorized equipment off existing roads could impact surface artifacts by 

damaging them or displacing them in their overall juxtaposition with other artifacts. 

Maintaining the integrity of a historical site is important to understanding the significance 

of the site and the artifacts found therein. Non-treatment of infested land would likely 

later result in more intensive and extensive treatment of that infested land. Most of the 

non-public lands that would be affected have already been heavily disturbed and any 

artifacts on them likely impacted. Consequently, it is unlikely that additional carbaryl 

bait treatments would result in additional impacts on cultural properties. 

With no treatment of grasshoppers on public lands, aerial application of insecticides off 

public lands would likely increase. However, most if not all of the areas likely to be 

treated have been heavily disturbed in the past, and any artifacts on them likely impacted. 

Consequently, it is unlikely that these aerial treatments would result in additional impacts 

on cultural properties. 

Motorized vehicles (pick-up trucks and/or ATV’s) may be used to treat portions of the 

affected areas. This would create a risk of impacting cultural properties. The risk is 

small given that the off-road use of vehicles would create only minor soil disturbance, 

and the areas involved are not likely to contain significant sites of which public officials 

are not already aware. Known sites would be avoided to mitigate impacts. Any sites 

located during treatment activities would be reported, and avoided during continuing 

operations. Past similar grasshopper treatments throughout the state have not resulted in 

any known impacts to cultural properties. 

In addition to the treatments proposed under this alternative, a broad variety and number 

of activities throughout the project area could affect, or have affected, cultural resources. 

These activities and any cumulative impacts associated with them would occur, 

regardless of whether or not grasshoppers are treated. No direct, indirect or change in 

cumulative impacts on cultural resources in the area would occur due to implementation 

of the treatment alternative. 

To ensure that historical or cultural sites, monuments, buildings or artifacts of special 

concern are not adversely affected by program treatments, APHIS would confer with 

BLM, Forest Service or other appropriate land management agency or cultural resource 

specialists on a local level to protect these areas of special concern. APHIS also would 

confer with the appropriate tribal authority and with the BIA office at a local level to 

ensure that the timing and location of planned program treatments do not coincide or 

conflict with cultural events or observances, such as sundances, on tribal lands. 
17

5. Special Considerations for Certain Populations

a) Executive Order No. 12898, Federal Actions to Address Environmental

Justice in Minority Populations and Low-Income Populations

Executive Order (E.O.) 12898, Federal Actions To Address Environmental Justice in 

Minority Populations and Low-Income Populations, was signed by President Clinton on 

February 11, 1994 (59 Federal Register (FR) 7269). This E.O. requires each Federal 

agency to make achieving environmental justice part of its mission by identifying and 

addressing, as appropriate, disproportionately high and adverse human health or 

environmental effects of its programs, policies, and activities on minority populations and 

low-income populations. Consistent with this E.O., APHIS will consider the potential for 

disproportionately high and adverse human health or environmental effects on minority 

populations and low-income populations for any of its actions related to grasshopper 

suppression programs. 

The human population at most sites in grasshopper programs is diverse and lacks any 

special characteristics that implicate greater risk of adverse effects for any minority or 

low-income populations. A demographic review of the proposed project area revealed 

certain areas with large populations, Spanish-speaking populations and some with large 

American Indian tribal populations. Low-income farmers and ranchers would comprise, 

by far, the largest group affected by APHIS program efforts in this area of concern. 

When planning a site-specific action related to grasshopper infestations, APHIS considers 

the potential for disproportionately high and adverse human health or environmental 

impacts of its actions on minority and low-income populations before any proposed 

action. In doing so, APHIS program managers would work closely with representatives 

of these populations in the locale of planned actions through public meetings. 

b) Executive Order No. 13045, Protection of Children from Environmental 

Health Risks and Safety Risks

The increased scientific knowledge about the environmental health risks and safety risks 

associated with hazardous substance exposures to children and recognition of these issues 

in Congress and Federal agencies brought about legislation and other requirements to 

protect the health and safety of children. On April 21, 1997, President Clinton signed 

E.O. 13045, Protection of Children From Environmental Health Risks and Safety Risks 

(62 FR 19885). This E.O. requires each Federal agency, consistent with its mission, to 

identify and assess environmental health risks and safety risks that may 

disproportionately affect children and to ensure that its policies, programs, activities, and 

standards address those risks. APHIS has developed agency guidance for its programs to 

follow to ensure the protection of children (USDA, APHIS, 1999). 

Treatments used for grasshopper programs are primarily conducted on open rangelands 

where children would not be expected to be present during treatment or enter during the 

restricted entry period after treatment. Based on the 2019 review of the four insecticides 

and their use in programs, the risk assessment concludes that the likelihood of children 

being exposed to insecticides from a grasshopper program is very slight and that no 
18

disproportionate adverse effects to children are anticipated over the negligible effects to 

the general population. 

IV. Environmental Consequences

Each alternative described in this EA potentially has adverse environmental effects. The 

general environmental impacts of each alternative are discussed in detail in the 2002 and 

2019 EIS. The specific impacts of the alternatives are highly dependent upon the 

particular action and location of infestation. The principal concerns associated with the 

alternatives are: (1) the potential effects of insecticides on human health (including 

subpopulations that might be at increased risk); and (2) impacts of insecticides on 

nontarget organisms (including threatened and endangered species). 

APHIS has written human health and ecological risk assessments (HHERAs) to assess 

the insecticides and use patterns that are specific to the program. The risk assessments 

provide an in-depth technical analysis of the potential impacts of each insecticide to 

human health; and non-target fish and wildlife along with its environmental fate in soil, 

air, and water. The assessments rely on data required by the USEPA for pesticide product 

registrations, as well as peer-reviewed and other published literature. The HHERAs are 

heavily referenced in this Final. These Environmental Documents can be found at the 

following website: http://www.aphis.usda.gov/plant-health/grasshopper. 

A. Environmental Consequences of the Alternatives

Site-specific environmental consequences of the alternatives are discussed in this section.

1. No Action Alternative

Under this alternative, APHIS would not conduct a program to suppress grasshoppers. If 

APHIS does not participate in any grasshopper suppression program, Federal land 

management agencies, State agriculture departments, local governments, private groups 

or individuals, may not effectively combat outbreaks in a coordinated effort. Without the 

technical assistance and coordination that APHIS provides during grasshopper outbreaks, 

the uncoordinated programs could use insecticides that APHIS considers too 

environmentally harsh. Multiple treatments and excessive amount of insecticide could be 

applied in efforts to suppress or even locally eradicate grasshopper populations. There are 

approximately 100 pesticide products registered by USEPA for use on rangelands and 

against grasshoppers (Purdue University, 2018). It is not possible to accurately predict the 

environmental consequences of the No Action alternative because the type and amount of 

insecticides that could be used in this scenario are unknown. However, the environmental 

impacts could be much greater than under the APHIS led suppression program alternative 

due to lack of treatment knowledge or coordination among the groups.

The potential environmental impacts from the No Action alternative, where other 

agencies and land managers do not control outbreaks, stem primarily from grasshoppers 

consuming vast amounts of vegetation in rangelands and surrounding areas. 

Grasshoppers are general feeders, eating grasses and forbs first and often moving to 

cultivated crops. High grasshopper density of one or several species and the resulting 

defoliation may reach an economic threshold where the damage caused by grasshoppers 
19

exceeds the cost of controlling the grasshoppers. Researchers determined that during 

typical grasshopper infestation years, approximately 20% of forage rangeland is removed, 

valued at a dollar adjusted amount of $900 million. This value represents 32 to 63% of 

the total value of rangeland across the western states (Rashford et al., 2012). Other 

market and non-market values such as carbon sequestration, general ecosystem services, 

and recreational use may also be impacted by pest outbreaks in rangeland.

Vegetation damage during serious grasshopper outbreaks may be so severe that all 

grasses and forbs are destroyed; thus, plant growth is impaired for several years. Rare 

plants may be consumed during critical times of development such as seed production, 

and loss of important plant species, or seed production may lead to reduced diversity of 

rangeland habitats, potentially creating opportunities for the expansion of invasive and 

exotic weeds (Lockwood and Latchininsky, 2000). When grasshoppers consume plant 

cover, soil is more susceptible to the drying effects of the sun, making plant roots less 

capable of holding soil in place. Soil damage results in erosion and disruption of nutrient 

cycling, water infiltration, seed germination, and other ecological processes which are 

important components of rangeland ecosystems (Latchininsky et al., 2011).

When the density of grasshoppers reaches significantly high levels, grasshoppers begin to 

compete with livestock for food by reducing available forage (Wakeland and Shull, 1936; 

Belovsky, 2000; Pfadt, 2002; Branson et al., 2006; Bradshaw et al., 2018). Ranchers 

could offset some of the costs by leasing rangeland in another area and relocating their 

livestock, finding other means to feed their animals by purchasing hay or grain, or selling 

their livestock. Ranchers could also incur economic losses from personal attempts to 

control grasshopper damage. Local communities could see adverse economic impacts to 

the entire area. Grasshoppers that infest rangeland could move to surrounding croplands. 

Farmers could incur economic losses from attempts to chemically control grasshopper 

populations or due to the loss of their crops. The general public could see an increase in 

the cost of meat, crops, and their byproducts.

2. Insecticide Applications at Conventional Rates or Reduced Agent Area 

Treatments with Adaptive Management Strategy

Under Alternative 2, APHIS would participate in grasshopper programs with the option 

of using one of the insecticides carbaryl, diflubenzuron, or malathion, depending upon 

the various factors related to the grasshopper outbreak and the site-specific 

characteristics. The use of an insecticide would typically occur at half the conventional 

application rates following the RAATs strategy. APHIS would apply a single treatment to

affected rangeland areas in an attempt to suppress grasshopper outbreak populations by a 

range of 35 to 98 percent, depending upon the insecticide used. 

a) Carbaryl

Carbaryl is a member of the N-methyl carbamate class of insecticides, which affect the 

nervous system via cholinesterase inhibition. Inhibiting the enzyme acetylcholinesterase 

(AChE) causes nervous system signals to persist longer than normal. While these effects 

are desired in controlling insects, they can have undesirable impacts to non-target 

organisms that are exposed. The APHIS HHERA assessed available laboratory studies 
20

regarding the toxicity of carbaryl on fish and wildlife. In summary, the document 

indicates the chemical is highly toxic to insects, including native bees, honeybees, and 

aquatic insects; slightly to highly toxic to fish; highly to very highly toxic to most aquatic 

crustaceans, moderately toxic to mammals, minimally toxic to birds; moderately to 

highly toxic to several terrestrial arthropod predators; and slightly to highly toxic to larval 

amphibians (USDA APHIS, 2018a). 

The offsite movement and deposition of carbaryl after treatments is unlikely because it

does not significantly vaporize from the soil, water, or treated surfaces (Dobroski et al., 

1985). Temperature, pH, light, oxygen, and the presence of microorganisms and organic 

material are factors that contribute to how quickly carbaryl will degrade in water.

Hydrolysis, the breaking of a chemical bond with water, is the primary degradation 

pathway for carbaryl at pH 7 and above. In natural water, carbaryl is expected to degrade 

faster than in laboratory settings due to the presence of microorganisms. The half-lives of 

carbaryl in natural waters varied between 0.3 to 4.7 days (Stanley and Trial, 1980; 

Bonderenko et al., 2004). Degradation in the latter study was temperature dependent with 

shorter half-lives at higher temperatures. Aerobic aquatic metabolism of carbaryl reported 

half-life ranged of 4.9 to 8.3 days compared to anaerobic (without oxygen) aquatic 

metabolism range of 15.3 to 72 days (Thomson and Strachan, 1981; USEPA, 2003).

Carbaryl is not persistent in soil due to multiple degradation pathways including 

hydrolysis, photolysis, and microbial metabolism. Little transport of carbaryl through 

runoff or leaching to groundwater is expected due to the low water solubility, moderate 

sorption, and rapid degradation in soils. There are no reports of carbaryl detection in 

groundwater, and less than 1% of granule carbaryl applied to a sloping plot was detected 

in runoff (Caro et al., 1974).

Acute and chronic risks to mammals are expected to be low to moderate based on the 

available toxicity data and conservative assumptions that were used to evaluate risk. 

There is the potential for impacts to small mammal populations that rely on terrestrial 

invertebrates for food. However, based on the toxicity data for terrestrial plants, minimal 

risks of indirect effects are expected to mammals that rely on plant material for food. 

Carbaryl has a reported half-life on vegetation of three to ten days, suggesting mammal 

exposure would be short-term. Direct risks to mammals from carbaryl bait applications is 

expected to be minimal based on oral, dermal, and inhalation studies (USDA APHIS, 

2018a).

A number of studies have reported no effects on bird populations in areas treated with 

carbaryl (Buckner et al., 1973; Richmond et al., 1979; McEwen et al., 1996). Some 

applications of formulated carbaryl were found to cause depressed AChE levels (Zinkl et 

al., 1977; Gramlich, 1979); however, the doses were twice those proposed for the full 

coverage application in the grasshopper program.

While sublethal effects have been noted in fish with depressed AChE, as well as some 

impacts to amphibians (i.e. days to metamorphosis) and aquatic invertebrates in the field 

due to carbaryl, the application rates and measured aquatic residues observed in these 

studies are well above values that would be expected from current program operations. 

Indirect risks to amphibian and fish species can occur through the loss of habitat or 
21

reduction in prey, yet data suggests that carbaryl risk to aquatic plants that may serve as 

habitat, or food, for fish and aquatic invertebrates is very low.

Product use restrictions appear on the USEPA-approved label and attempt to keep 

carbaryl out of waterways. Carbaryl must not be applied directly to water, or to areas 

where surface water is present (USEPA, 2012c). The USEPA-approved use rates and 

patterns and the additional mitigations imposed by the grasshopper program, such as 

using RAATs and application buffers, where applicable, further minimize aquatic 

exposure and risk.

The majority of rangeland plants require insect-mediated pollination. Native, solitary bee 

species are important pollinators on western rangeland (Tepedino, 1979). Potential 

negative effects of insecticides on pollinators are of concern because a decrease in their 

numbers has been associated with a decline in fruit and seed production of plants. 

Laboratory studies have indicated that bees are sensitive to carbaryl applications but the 

studies were at rates above those proposed in the program. The reduced rates of carbaryl 

used in the program and the implementation of application buffers should significantly 

reduce exposure of carbaryl applications to pollinators. In areas of direct application 

where impacts may occur, alternating swaths and reduced rates (i.e., RAATs) would 

reduce risk. Potential negative effects of grasshopper program insecticides on bee 

populations may also be mitigated by the more common use of carbaryl baits than the 

ULV spray formulation. Studies with carbaryl bran bait have found no sublethal effects 

on adults or larvae bees (Peach et al., 1994, 1995).

Carbaryl can cause cholinesterase inhibition (i.e., overstimulate the nervous system) in 

humans resulting in nausea, headaches, dizziness, anxiety, and mental confusion, as well 

as convulsions, coma, and respiratory depression at high levels of exposure (NIH, 2009a;

Beauvais, 2014). USEPA classifies carbaryl as “likely to be carcinogenic to humans” 

based on vascular tumors in mice (USEPA, 2007, 2015a, 2017a).

USEPA regulates the amount of pesticide residues that can remain in or on food or feed 

commodities as the result of a pesticide application. The agency does this by setting a 

tolerance, which is the maximum residue level of a pesticide, usually measured in parts 

per million (ppm), that can legally be present in food or feed. USEPA-registered carbaryl 

products used by the grasshopper program are labeled with rates and treatment intervals 

that are meant to protect livestock and keep chemical residues in cattle at acceptable 

levels (thereby protecting human health). While livestock and horses may graze on 

rangeland the same day that the land is sprayed, in order to keep tolerances to acceptable 

levels, carbaryl spray applications on rangeland are limited to half a pound active 

ingredient per acre per year (USEPA, 2012c). The grasshopper program would treat at or 

below use rates that appear on the label, as well as follow all appropriate label 

mitigations, which would ensure residues are below the tolerance levels.

Adverse human health effects from the proposed program ULV applications of the 

carbaryl spray (Sevin® XLR Plus) and bait applications of the carbaryl 5% and 2% baits 

formulations to control grasshoppers are not expected based on low potential for human 

exposure to carbaryl and the favorable environmental fate and effects data. Technical 
22

grade (approximately 100% of the insecticide product is composed of the active 

ingredient) carbaryl exhibits moderate acute oral toxicity in rats, low acute dermal 

toxicity in rabbits, and very low acute inhalation toxicity in rats. Technical carbaryl is not 

a primary eye or skin irritant in rabbits and is not a dermal sensitization in guinea pig 

(USEPA, 2007). This data can be extrapolated and applied to humans revealing low 

health risks associated with carbaryl.

The Sevin® XLR Plus formulation, which contains a lower percent of the active 

ingredient than the technical grade formulation, is less toxic via the oral route, but is a 

mild irritant to eyes and skin. The proposed use of carbaryl as a ULV spray or a bait, use 

of RAATs, and adherence to label requirements, substantially reduces the potential for 

exposure to humans. Program workers are the most likely human population to be 

exposed. APHIS does not expect adverse health risks to workers based on low potential 

for exposure to carbaryl when applied according to label directions and use of personal 

protective equipment (PPE) (e.g., long-sleeved shirt and long pants, shoes plus socks, 

chemical-resistant gloves, and chemical-resistant apron) (USEPA, 2012c) during loading 

and applications. APHIS quantified the potential health risks associated with accidental 

worker exposure to carbaryl during mixing, loading, and applications. The quantitative 

risk evaluation results indicate no concerns for adverse health risk for program workers 

(http://www.aphis.usda.gov/plant-health/grasshopper).

Adherence to label requirements and additional program measures designed to reduce 

exposure to workers and the public (e.g., mitigations to protect water sources, mitigations 

to limit spray drift, and restricted-entry intervals) result in low health risk to all human 

population segments.

b) Diflubenzuron

Diflubenzuron is a restricted use pesticide (only certified applicators or persons under 

their direct supervision may make applications) registered with USEPA as an insect 

growth regulator. It specifically interferes with chitin synthesis, the formation of the 

insect’s exoskeleton. Larvae of affected insects are unable to molt properly. While this 

effect is desirable in controlling certain insects, it can have undesirable impacts to nontarget organisms that are exposed.

USEPA considers diflubenzuron relatively non-persistent and immobile under normal use 

conditions and stable to hydrolysis and photolysis. The chemical is considered unlikely to 

contaminate ground water or surface water (USEPA, 1997). The vapor pressure of 

diflubenzuron is relatively low, as is the Henry’s Law Constant value, suggesting the 

chemical will not volatilize readily into the atmosphere from soil, plants or water. 

Therefore, exposure from volatilization is expected to be minimal. Due to its low 

solubility (0.2 mg/L) and preferential binding to organic matter, diflubenzuron seldom 

persists more than a few days in water (Schaefer and Dupras, 1977; Schaefer et al., 

1980). Mobility and leachability of diflubenzuron in soils is low, and residues are usually 

not detectable after seven days (Eisler, 2000). Aerobic aquatic half-life data in water and 

sediment was reported as 26.0 days (USEPA, 1997). Diflubenzuron applied to foliage 

remains adsorbed to leaf surfaces for several weeks with little or no absorption or 

translocation from plant surfaces (Eisler, 1992, 2000). Diflubenzuron treatments are 
23

expected to have minimal effects on terrestrial plants. Both laboratory and field studies 

demonstrate no effects using diflubenzuron over a range of application rates, and the 

direct risk to terrestrial plants is expected to be minimal (USDA APHIS, 2018c).

Dimilin® 2L is labeled with rates and treatment intervals that are meant to protect 

livestock and keep residues in cattle at acceptable levels (thereby, protecting human 

health). Tolerances are set for the amount of diflubenzuron that is allowed in cattle fat 

(0.05 ppm) and meat (0.05 ppm) (40 CFR Parts 180.377). The grasshopper program 

would treat at application rates indicated on product labels or lower, which should ensure 

approved residues levels. 

APHIS’ literature review found that on an acute basis, diflubenzuron is considered toxic 

to some aquatic invertebrates and practically non-toxic to adult honeybees. However, 

diflubenzuron is toxic to larval honeybees (USEPA, 2018). It is slightly nontoxic to 

practically nontoxic to fish and birds and has very slight acute oral toxicity to mammals, 

with the most sensitive endpoint from exposure being the occurrence of 

methemoglobinemia (a condition that impairs the ability of the blood to carry oxygen). 

Minimal direct risk to amphibians and reptiles is expected, although there is some 

uncertainty due to lack of information (USDA APHIS, 2018c; USEPA, 2018).

Risk is low for most non-target species based on laboratory toxicity data, USEPA 

approved use rates and patterns, and additional mitigations such as the use of lower rates 

and RAATs that further reduces risk. Risk is greatest for sensitive terrestrial and aquatic 

invertebrates that may be exposed to diflubenzuron residues.

In a review of mammalian field studies, Dimilin® applications at a rate of 60 to 280 g 

a.i./ha had no effects on the abundance and reproduction in voles, field mice, and shrews 

(USDA FS, 2004). These rates are approximately three to 16 times greater than the 

highest application rate proposed in the program. Potential indirect impacts from 

application of diflubenzuron on small mammals includes loss of habitat or food items. 

Mice on treated plots consumed fewer lepidopteran (order of insects that includes 

butterflies and moths) larvae compared to controls; however, the total amount of food 

consumed did not differ between treated and untreated plots. Body measurements, 

weight, and fat content in mice collected from treated and non-treated areas did not differ. 

Poisoning of insectivorous birds by diflubenzuron after spraying in orchards at labeled 

rates is unlikely due to low toxicity (Muzzarelli, 1986). The primary concern for bird 

species is related to an indirect effect on insectivorous species from a decrease in insect 

prey. At the proposed application rates, grasshoppers have the highest risk of being 

impacted while other taxa have a much reduced risk because the lack of effects seen in 

multiple field studies on other taxa of invertebrates at use rates much higher than those 

proposed for the program. Shifting diets in insectivorous birds in response to prey 

densities is not uncommon in undisturbed areas (Rosenberg et al., 1982; Cooper et al., 

1990; Sample et al., 1993).

Indirect risk to fish species can be defined as a loss of habitat or prey base that provides 

food and shelter for fish populations, however these impacts are not expected based on 
24

the available fish and invertebrate toxicity data (USDA APHIS, 2018c). A review of 

several aquatic field studies demonstrated that when effects were observed it was at 

diflubenzuron levels not expected from program activities (Fischer and Hall, 1992;

USEPA, 1997; Eisler, 2000; USDA FS, 2004). 

Diflubenzuron applications have the potential to affect chitin production in various other 

beneficial terrestrial invertebrates. Multiple field studies in a variety of application 

settings, including grasshopper control, have been conducted regarding the impacts of 

diflubenzuron to terrestrial invertebrates. Based on the available data, sensitivity of 

terrestrial invertebrates to diflubenzuron is highly variable depending on which group of 

insects and which life stages are being exposed. Immature grasshoppers, beetle larvae, 

lepidopteran larvae, and chewing herbivorous insects appear to be more susceptible to 

diflubenzuron than other invertebrates. Within this group, however, grasshoppers appear 

to be more sensitive to the proposed use rates for the program. Honeybees, parasitic 

wasps, predatory insects, and sucking insects show greater tolerance to diflubenzuron 

exposure (Murphy et al., 1994; Eisler, 2000; USDA FS, 2004). 

Diflubenzuron is moderately toxic to spiders and mites (USDA APHIS, 2018c). Deakle 

and Bradley (1982) measured the effects of four diflubenzuron applications on predators 

of Heliothis spp. at a rate of 0.06 lb a.i./ac and found no effects on several predator 

groups. This supported earlier studies by Keever et al. (1977) that demonstrated no 

effects on the arthropod predator community after lications of diflubenzuron in cotton 

fields. Grasshopper integrated pest management (IPM) field studies have shown 

diflubenzuron to have a minimal impact on ants, spiders, predatory beetles, and 

scavenger beetles. There was no significant reduction in populations of these species 

from seven to 76 days after treatment. Although ant populations exhibited declines of up 

to 50 percent, these reductions were temporary, and population recovery was described as 

immediate (Catangui et al., 1996).

Insecticide applications to rangelands have the potential to impact pollinators, and in turn, 

vegetation and various rangeland species that depend on pollinated vegetation. Based on 

the review of laboratory and field toxicity data for terrestrial invertebrates, applications of 

diflubenzuron are expected to have minimal risk to pollinators of terrestrial plants. The 

use of RAATs provide additional benefits by using reduced rates and creating untreated 

swaths within the spray block that will further reduce the potential risk to pollinators.

Adverse human health effects from ground or aerial ULV applications of diflubenzuron 

to control grasshoppers are not expected based on the low acute toxicity of diflubenzuron 

and low potential for human exposure. The adverse health effects of diflubenzuron to 

mammals and humans involves damage to hemoglobin in blood and the transport of 

oxygen. Diflubenzuron causes the formation of methemoglobin. Methemoglobin is a 

form of hemoglobin that is not able to transport oxygen (USDA FS, 2004). USEPA 

classifies diflubenzuron as non-carcinogenic to humans (USEPA, 2015b). 

Program workers adverse health risks are not likely when diflubenzuron is applied 

according to label directions that reduce or eliminate exposures. Adverse health risk to 

the general public in treatment areas is not expected due to the low potential for exposure 
25

resulting from low population density in the treatment areas, adherence to label 

requirements, program measures designed to reduce exposure to the public, and low 

toxicity to mammals.

c) Malathion

Malathion is a broad-spectrum organophosphate insecticide widely used in agriculture on 

various food and feed crops, homeowner yards, ornamental nursery stock, building 

perimeters, pastures and rangeland, and regional pest eradication programs. The 

chemical’s mode of action is through AChE inhibition, which disrupts nervous system 

function. While these effects are desired in controlling insects, they can have undesirable 

impacts to non-target organisms that are exposed to malathion. The grasshopper program 

currently uses the malathion end-use product Fyfanon® ULV AG, applied as a spray by 

ground or air.

Volatility is not expected to be a major pathway of exposure based on the low vapor 

pressure and Henry’s Law constant that have been reported for malathion. The 

atmospheric vapor phase half-life of malathion is five hours (NIH, 2009b). Malathion’s 

half-life in pond, lake, river, and other natural waters varied from 0.5 days to ten days, 

depending on pH (Guerrant et al., 1970), persisting longer in acidic aquatic environments. 

The reported half-life in water and sediment for the anaerobic aquatic metabolism study 

was 2.5 days at a range of pH values from 7.8 to 8.7 (USEPA, 2006). The persistence of 

malathion in soils depends primarily on microorganism activity, pH, and organic matter 

content. The persistence of malathion is decreased with microbial activity, moisture, and 

high pH (USEPA, 2016a) and the half-life of malathion in natural soil varies from two 

hours (Miles and Takashima, 1991) to 11 days (Neary, 1985; USEPA, 2006). 

Malathion and associated degradates, in general, are soluble and do not adsorb strongly to 

soils (USEPA, 2000a). Inorganic degradation of malathion may be more important in 

soils that are relatively dry, alkaline, and low in organic content, such as those that 

predominate in the western program areas. Adsorption to organic matter and rapid 

degradation make it unlikely that detectable quantities of malathion would leach to 

groundwater (LaFleur, 1979). Malathion degradation products also have short half-lives. 

Malaoxon, the major malathion degradation product of toxicological concern, has halflives less than one day in a variety of soil types (USEPA, 2016a). The half-life of 

malathion on foliage has been shown to range from one to six days (El-Refai and 

Hopkins, 1972; Nigg, 1986; Matsumara, 1985; USDA FS, 2008).

While livestock and horses may graze on rangeland the same day that the land is treated 

with malathion, the products used by the grasshopper program are labeled with rates and 

treatment intervals that are meant to protect livestock. Tolerances are set for the amount 

of malathion that is allowed in cattle fat (4 ppm), meat (4 ppm), and meat byproducts (4 

ppm) (40 CFR Parts 180.111). The grasshopper program would treat at application rates 

indicated on product labels or lower, which would ensure approved residues levels. In 

addition, the program would make only one application a year.

USEPA found malathion moderately toxic to birds on a chronic basis, slightly toxic to 

mammals through dietary exposure, and acutely toxic to aquatic species (including 
26

freshwater as well as estuarine and marine species) (USEPA, 2000b, 2016b). Toxicity to 

aquatic vertebrates such as fish and larval amphibians, and aquatic invertebrates is 

variable based on test species and conditions. The data available on impacts to fish from 

malathion suggest effects could occur at levels above those expected from program 

applications. Consumption of contaminated prey is not expected to be a significant 

pathway of exposure for aquatic species based on expected residues and malathion’s BCF 

(USEPA, 2016a; USDA APHIS, 2018d). Indirect effects to fish from impacts of 

malathion applications to aquatic plants are not expected (USDA APHIS, 2018d).

USEPA considers malathion highly toxic to bees if exposed to direct treatment on 

blooming crops or weeds. The Fyfanon® ULV AG label indicates not to apply product or 

allow it to drift to blooming crops or weeds while bees are actively visiting the treatment 

area (USEPA, 2012a). Toxicity to other terrestrial invertebrates is variable based on the 

test organism and test conditions however malathion is considered toxic to most 

terrestrial invertebrates (USEPA, 2016b).

Indirect risks to mammals resulting from the loss of plants that serve as a food source 

would also be low due to the low phytotoxicity of malathion. The other possible indirect 

effect that should be considered is loss of invertebrate prey for those mammals that 

depend on insects and other invertebrates as a food source. Insects have a wide variety of 

sensitivities to malathion and a complete loss of invertebrates from a treated area is not 

expected because of low program rates and application techniques. In addition, the aerial 

and ground application buffers and untreated swaths provide refuge for invertebrates that 

serve as prey for insectivorous mammals and would expedite repopulation of areas that 

may have been treated.

APHIS expects that direct avian acute and chronic effects would be minimal for most 

species (USDA APHIS, 2018d). The preferred use of RAATs during application reduces 

these risks by reducing residues on treated food items and reducing the probability that 

they will only feed on contaminated food items. In addition, malathion degrades quickly 

in the environment and residues on food items are not expected to persist. Indirect effects 

on birds from the loss of habitat and food items are not expected because of malathion’s 

low toxicity to plants and the implementation of RAATs that would reduce the potential 

impacts to invertebrates that serve as prey for avian species. Several field studies did not 

find significant indirect effects of malathion applications on avian fecundity (Dinkins et 

al., 2002; George et al., 1995; Howe, 1993; Howe et al., 1996; Norelius and Lockwood, 

1999; Pascual, 1994).

Available toxicity data demonstrates that amphibians are less sensitive to malathion than 

fish. Program malathion residues are more than 560 times below the most sensitive acute 

toxicity value for amphibians. Sublethal effects, such as developmental delays, reduced 

food consumption and body weight, and teratogenesis (developmental defects that occur 

during embryonic or fetal growth), have been observed at levels well above those 

assessed from the program’s use of malathion (USDA APHIS, 2018d). Program 

protection measures for aquatic water bodies and the available toxicity data for fish, 

aquatic invertebrates, and plants suggest low indirect risks related to reductions in habitat 

or aquatic prey items from malathion treatments.
27

Available data on malathion reptile toxicity suggest that, with the use of program 

measures, no lethal or sublethal impacts would be anticipated (USDA APHIS, 2015). 

Indirect risk to reptiles from the loss of food items is expected to be low due to the low 

application rates and implementation of preferred program measures such as RAATs 

(USDA APHIS, 2018d).

The risk to aquatic vertebrates and invertebrates is low for most species; however, some 

sensitive species that occur in shallow water habitats may be at risk. Program measures 

such application buffer zones, drift mitigation measures and the use of RAATs will 

reduce these risks.

Risks to terrestrial invertebrate populations are anticipated based on the available toxicity 

data for invertebrates and the broad spectrum activity of malathion (Swain, 1986; Quinn 

et al., 1991). The risk to terrestrial invertebrates can be reduced by the implementation of 

application buffers and the use of RAATs, which would reduce exposure and create 

refuge areas where malathion impacts would be reduced or eliminated. Smith et al. 

(2006) conducted field studies to evaluate the impacts of grasshopper treatments to nontarget terrestrial invertebrates and found minimal impacts when making reduced rate 

applications with a reduced coverage area (i.e. RAATs) for a ULV end-use product of 

malathion. Impacts to pollinators have the potential to be significant, based on available 

toxicity data for honeybees that demonstrate high contact toxicity from malathion 

exposures (USDA APHIS, 2018d). However, risk to pollinators is reduced because of the 

short residual toxicity of malathion. In addition, the incorporation of other mitigation 

measures in the program, such as the use of RAATs and wind speed and direction 

mitigations that are designed to minimize exposure, reduce the potential for populationlevel impacts to terrestrial invertebrates.

Adverse human health effects from ULV applications of malathion to control 

grasshopper are not expected based on the low mammalian acute toxicity of malathion 

and low potential for human exposure. Malathion inhibits AChE in the central and 

peripheral nervous system with clinical signs of neurotoxicity that include tremors, 

salivation, urogenital staining, and decreased motor activity. USEPA indicates that 

malathion has “suggestive evidence of carcinogenicity but not sufficient to assess human 

carcinogenic potential” (USEPA, 2016c). 

Adverse health risks to program workers and the general public from malathion exposure 

are also not expected due to low potential for exposure. APHIS treatments are conducted 

in rangeland areas consisting of widely scattered, single, rural dwellings in ranching 

communities, where agriculture is a primary industry. Label requirements to reduce 

exposure include minimizing spray drift, avoidance of water bodies and restricted entry 

interval. Program measures such as applying malathion once per season, lower 

application rates, application buffers and other measures further reduce the potential for 

exposure to the public.

d) Reduced Area Agent Treatments (RAATs) 

The use of RAATS is the most common application method for all program insecticides 

and would continue to be so except in rare pest conditions that warrant full coverage and 
28

higher rates. The goal of the RAATs strategy is to suppress grasshopper populations to a 

desired level, rather than to reduce those populations to the greatest possible extent. This 

strategy has both economic and environmental benefits. APHIS would apply a single 

application of insecticide per year, typically using a RAATs strategy that decreases the 

rate of insecticide applied by either using lower insecticide concentrations, or by 

alternating one or more treatment swaths. Usually RAATs applications use the latter 

strategy but often use both simultaneously. The RAATs strategy suppresses grasshoppers 

within treated swaths, while conserving grasshopper predators and parasites in swaths 

that are not treated. 

The concept of reducing the treatment area of insecticides while also applying less 

insecticide per treated acre was developed in 1995, with the first field tests of RAATs in 

Wyoming (Lockwood and Schell, 1997). Applications can be made either aerially or with 

ground-based equipment (Deneke and Keyser, 2011). Studies using the RAATs strategy 

have shown good control (up to 85% of that achieved with a traditional blanket 

insecticide application) at a significantly lower cost and less insecticide, and with a 

markedly higher abundance of non-target organisms following application (Lockwood et 

al., 2000; Deneke and Keyser, 2011). Levels of control may also depend on variables 

such as body size of targeted grasshoppers, growth rate of forage, and the amount of 

coverage obtained by the spray applications (Deneke and Keyser, 2011). Control rates 

may also be augmented by the necrophilic and necrophagic behavior of grasshoppers, in 

which grasshoppers are attracted to volatile fatty acids emanating from cadavers of dead 

grasshoppers and move into treated swaths to cannibalize cadavers (Lockwood et al., 

2002; Smith and Lockwood, 2003). Under optimal conditions, RAATs decrease control 

costs, as well as host plant losses and environmental effects (Lockwood et al., 2000; 

Lockwood et al., 2002). 

The efficacy of a RAATs strategy in reducing grasshoppers is, therefore, less than 

conventional treatments and more variable. Foster et al. (2000) reported that grasshopper 

mortality using RAATs was reduced 2 to 15% from conventional treatments, depending 

on the insecticide, while Lockwood et al. (2000) reported 0 to 26% difference in 

mortality between conventional and RAATs methods. APHIS will consider the effects of 

not suppressing grasshoppers to the greatest extent possible as part of the treatment 

planning process. 

RAATs reduces treatment costs and conserves non-target biological resources in 

untreated areas. The potential economic advantages of RAATs was proposed by Larsen 

and Foster (1996), and empirically demonstrated by Lockwood and Schell (1997). 

Widespread efforts to communicate the advantages of RAATs across the Western States 

were undertaken in 1998, and have continued on an annual basis. The viability of RAATs 

at an operational scale was initially demonstrated by Lockwood et al. (2000), and 

subsequently confirmed by Foster et al. (2000). The first government agencies to adopt 

RAATs in their grasshopper suppression programs were the Platte and Goshen County 

Weed and Pest Districts in Wyoming; they also funded research at the University of 

Wyoming to support the initial studies in 1995. This method is now commonly used by 

government agencies and private landowners in States where grasshopper control is 

required.
29

Reduced rates should prove beneficial for the environment. All APHIS grasshopper 

treatments using carbaryl, diflubenzuron, or malathion are conducted in adherence with 

USEPA-approved label directions. Labeled application rates for grasshopper control tend 

to be lower than rates used against other pests. In addition, use rates proposed for 

grasshopper control by APHIS are lower than rates used by private landowners.

B. Other Environmental Considerations

1. Cumulative Impacts

Cumulative impact, as defined in the Council on Environmental Quality (CEQ) NEPA 

implementing regulations (40 CFR § 1508.7) “is the impact on the environment which 

results from the incremental impact of the action when added to the past, present, and 

reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) 

or person undertakes such actions. Cumulative impacts can result from individually 

minor but collectively significant actions taking place over a period of time.”

Potential cumulative impacts associated with the No Action alternative where APHIS 

would not take part in any grasshopper suppression program include the continued 

increase in grasshopper populations and potential expansion of populations into 

neighboring range and cropland. In addition, State and private land managers could apply 

insecticides to manage grasshopper populations however, land managers may opt not to 

use RAATs, which would increase insecticides applied to the environment. Increased

insecticide use from the lack of coordination and RAAT applications where suitable 

could increase the exposure risk to non-target species and the environment. In addition, 

land managers may not employ the extra program measures designed to reduce exposure 

to the public and the environment. 

Potential cumulative impacts associated with the Preferred Alternative are not expected 

to be significant because the program applies an insecticide application once during a 

treatment. The program may treat an area with different insecticides, but does not overlap 

the treatments. The program does not mix or combine insecticides. Based on historical 

outbreaks in the United States, the probability of an outbreak occurring in the same area 

where treatment occurred in the previous year is unlikely; however, given time, 

populations eventually will reach economically damaging thresholds and require 

treatment. The insecticide application reduces the insect population down to levels that 

cause an acceptable level of economic damage. The duration of treatment activity, which 

is relatively short since it is a one-time application, and the lack of repeated treatments in 

the same area in the same year reduce the possibility of significant cumulative impacts.

Potential cumulative impacts resulting from the use of insecticides include insect pest 

resistance, synergistic chemical effects, chemical persistence and bioaccumulation in the 

environment. The program use of reduced insecticide application rates (i.e. ULV and 

RAATs) are expected to mitigate the development of insect resistance to the insecticides.

Grasshopper outbreaks in the United States occur cyclically so applications do not occur 

to the same population over time further eliminating the selection pressure increasing the 

chances of insecticide resistance.
30

The insecticides proposed for use in the program have a variety of agricultural and nonagricultural uses. There may be an increased use of these insecticides in an area under 

suppression when private, State, or Federal entities make applications to control other 

pests. However, the vast majority of the land where program treatments occur is 

uncultivated rangeland and additional treatments by land owners or managers are very 

uncommon making possible cumulative or synergistic chemical effects extremely 

unlikely. 

The insecticides proposed for use in the grasshopper program are not anticipated to 

persist in the environment or bioaccumulate. Therefore, a grasshopper outbreak that 

occurs in an area previously treated for grasshoppers is unlikely to cause an accumulation 

of insecticides from previous program treatments.

The Bureau of Land Management could apply herbicides for the control of federal 

noxious weeds throughout some of the potential grasshopper suppression areas. The 

timing of such treatments should not coincide, so there would be little reason to suspect 

that any adverse synergistic chemical effects would occur. In any event, before any 

APHIS program, discussions would be held with land-managing officials to ensure that 

the two programs would not cause increased injurious effects to any treatment area. 

Private agricultural entities could apply herbicides or insecticides to their cropland during 

times which could coincide with APHIS programs. APHIS’ policy requires that the 

grasshoppers may only be treated on private rangelands, so that cumulative impacts 

would not result. 

2. Executive Order No. 12898, Federal Actions to Address Environmental

Justice in Minority Populations and Low-Income Populations

Federal agencies identify and address the disproportionately high and adverse human 

health or environmental effects of their proposed activities, as described in Executive 

Order (EO) 12898, “Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations.”

The human population at most sites in grasshopper programs is diverse and lacks any 

special characteristics that implicate greater risks of adverse effects for any minority or 

low-income populations. A demographic review of the proposed project area revealed 

certain areas with large populations, Spanish-speaking populations and some with large 

American Indian tribal populations. Low-income farmers and ranchers would comprise, 

by far, the largest group affected by APHIS program efforts in this area of concern. 

When planning a site-specific action related to grasshopper infestations, APHIS considers 

the potential for disproportionately high and adverse human health or environmental 

impacts of its actions on minority and low-income populations before any proposed 

action. In doing so APHIS program managers would work closely with representatives 

of these populations in the locale of planned actions through public meetings. 

APHIS intervention to locally suppress damaging grasshopper infestations would stand to 

greatly benefit, rather than harm, low-income farmers and ranchers by helping them to 
31

control grasshopper threats to their livelihood. Suppressing grasshopper infestations on 

adjacent public or private rangelands would increase inexpensive available forage for 

their livestock and would significantly decrease economic losses to their crop lands by 

invading grasshoppers. Such would obviate the need to perform additional expensive 

crop pesticide treatments or to provide supplemental feed to their livestock which would 

further impact low-income individuals. 

In past grasshopper programs, the U.S. Department of the Interior’s (USDI) Bureau of 

Land Management or Bureau of Indian Affairs have notified the appropriate APHIS State 

Plant Health Director when any new or potentially threatening grasshopper infestations is 

discovered on BLM lands or tribal lands held in trust and administered by BIA. Thus, 

APHIS has cooperated with BIA when grasshopper programs occur on Indian tribal 

lands. For local Indian populations, APHIS program managers would work with BIA 

and local tribal councils to communicate information to tribal organizations and 

representatives when programs have the potential to impact the environment of their 

communities, lands or cultural resources. In past grasshopper programs, APHIS has 

worked cooperatively with American Indian groups and would continue to do so in the 

future. 

3. Executive Order No. 13045, Protection of Children from 

Environmental Health Risks and Safety Risks

Federal agencies consider a proposed action’s potential effects on children to comply 

with EO 13045, “Protection of Children from Environmental Health Risks and Safety 

Risks.” This EO requires each Federal agency, consistent with its mission, to identify and 

assess environmental health and safety risks that may disproportionately affect children 

and to ensure its policies, programs, activities, and standards address disproportionate 

risks to children that result from environmental health risks or safety risks. APHIS has 

developed agency guidance for its programs to follow to ensure the protection of children 

(USDA APHIS, 1999).

APHIS’ HHERAs evaluated the potential exposure to each insecticide used in the 

program and risks associated with these insecticides to residents, including children. The 

HHERAs for the proposed program insecticides, located at 

http://www.aphis.usda.gov/plant-health/grasshopper, suggest that no disproportionate 

risks to children, as part of the general public, are anticipated.

The human health risk assessment for the 2019 EIS analyzed the efforts of exposure to 

children from the four insecticides. Based on review of the insecticides and their use in 

the grasshopper program, the risk assessment concluded that the likelihood of children 

being exposed to insecticides is very slight and that no disproportionate adverse effects to 

children are anticipated over the negligible effects to the general population. Treatments 

are conducted on open rangelands where children would not be expected to be present 

during treatment or to enter should there be any restricted entry period after treatment. 

Impacts on children would be minimized by the implementation of the Treatment 

Guidelines:
32

Aerial Broadcast Applications of Liquid Insecticides

• Notify all residents in treatment areas, or their designated representatives, prior to 

proposed operations. Advise them of the control method to be used, the proposed 

method of application, and precautions to be taken (e.g., advise parents to keep 

children and pets indoors during ULV treatment). Refer to label 

recommendations related to restricted entry period. 

• No treatments would occur over congested urban areas. For all flights over 

congested areas, the contractor must submit a plan to the appropriate FAA District 

Office and this office must approve of the plan; a letter of authorization signed by 

the city or town authorities must accompany each plan. Whenever possible, plan 

aerial ferrying and turnaround routes to avoid flights over congested areas, bodies 

of water, and other sensitive areas that are not to be treated. 

Aerial Application of Dry Insecticidal Bait

• Do not apply within 500 feet of any school or recreational facility. 

Ultra-Low-Volume Aerial Application of Liquid Insecticides 

• Do not spray while school buses are operating in the treatment area.

• Do not apply within 500 feet of any school or recreational facility.

Based on the analysis in the protection measures, we have determined that there would be 

no significant impact within any potential treatment zone of the area of concern. 

4. Tribal Consultation

Executive Order 13175 "Consultation and Coordination with Indian Tribal 

Governments," calls for agency communication and collaboration with tribal officials 

when proposed Federal actions have potential tribal implications. The Archaeological 

Resources Protection Act of 1979 (16 U.S.C. §§ 470aa-mm), secures the protection of 

archaeological resources and sites on public and tribal lands.

Prior to the treatment season, program personnel notify Tribal land managers of the 

potential for grasshopper and Mormon cricket outbreaks on their lands. Consultation with 

local Tribal representatives takes place prior to treatment programs to inform fully the 

Tribes of possible actions APHIS may take on Tribal lands. Treatments typically do not 

occur at cultural sites, and drift from a program treatment at such locations is not 

expected to adversely affect natural surfaces, such as rock formations and carvings. 

APHIS would also confer with the appropriate Tribal authority to ensure that the timing 

and location of a planned program treatment does not coincide or conflict with cultural 

events or observances on Tribal lands.
33

5. Executive Order 13186, Responsibilities of Federal Agencies to Protect 

Migratory Birds

The Migratory Bird Treaty Act (MBTA) of 1918 (16 U.S.C. 703–712) established a 

Federal prohibition, unless permitted by regulations, to pursue, hunt, take, capture, kill, 

attempt to take, capture or kill, possess, offer for sale, sell, offer to purchase, purchase, 

deliver for shipment, ship, cause to be shipped, deliver for transportation, transport, cause 

to be transported, carry, or cause to be carried by any means whatever, receive for 

shipment, transportation or carriage, or export, at any time, or in any manner, any 

migratory bird or any part, nest, or egg of any such bird.

Executive Order 13186 directs Federal agencies taking actions with a measurable 

negative effect on migratory bird populations to develop and implement a Memorandum 

of Understanding with the USFWS that promotes the conservation of migratory bird 

populations. On August 2, 2012, a Memorandum of Understanding between APHIS and 

the USFWS was signed to facilitate the implementation of this Executive Order.

In accordance with Executive Order 13186, MBTA, APHIS will support the conservation 

intent of the migratory bird conventions by integrating bird conservation principles, 

measures, and practices into agency activities and by avoiding or minimizing, to the 

extent practicable, adverse impacts on migratory bird resources when conducting agency 

actions. Impacts are minimized as a result of buffers to water, habitat, nesting areas, 

riparian areas, and the use of RAATs. For any given treatment, only a portion of the 

environment will be treated, therefore minimizing potential impacts to migratory bird 

populations. 

6. Endangered Species Act

Section 7 of the Endangered Species Act (ESA) and its implementing regulations require 

Federal agencies to ensure their actions are not likely to jeopardize the continued 

existence of listed threatened or endangered (listed) species, or result in the destruction or 

adverse modification of critical habitat. Numerous federally-listed species and areas of 

designated critical habitat occur within the 17-State program area, although not all occur 

within or near potential grasshopper suppression areas or within the area under 

consideration by through this EA. 

APHIS considers whether listed species, species proposed for listing, experimental 

populations, or critical habitat are present in the proposed suppression area. Before 

treatments are conducted, APHIS contacts the U.S Fish and Wildlife Service (USFWS) or 

the National Marine Fisheries Service (NMFS) (where applicable) to determine if listed 

species are present in the suppression area, and whether mitigations or protection 

measures must be implemented to protect listed species or critical habitat. 

APHIS completed a programmatic Section 7 consultation with NMFS for use of carbaryl, 

malathion, and diflubenzuron to suppress grasshoppers in the 17-state program area 

because of the listed salmonid (Oncorhynchus spp.) and critical habitat. To minimize the 

possibility of insecticides from reaching salmonid habitat, APHIS implements the 

following protection measures:
34

• RAATs are used in all areas adjacent to salmonid habitat

• ULV sprays are used, which are between 50 and 66% of the USEPA 

recommended rate

• Insecticides are not aerially applied in 3,500 foot buffer zones for carbaryl or 

malathion or in 1,500 foot buffer zones for diflubenzuron along stream corridors

• Insecticides will not be applied when wind speeds exceed 10 miles per hour. 

APHIS will attempt to avoid insecticide application if the wind is blowing 

towards salmonid habitat

• Insecticide applications are avoided when precipitation is likely or during 

temperature inversions

APHIS determined that with the implementation of these measures, the grasshopper 

suppression program may affect, but is not likely to adversely affect listed salmonids or 

designated critical habitat in the program area. NMFS concurred with this determination 

in a letter dated April 12, 2010.

APHIS submitted a programmatic biological assessment and requested consultation with 

USFWS on March 9, 2015 for use of carbaryl, malathion, diflubenzuron, and 

chlorantraniliprole for grasshopper suppression in the 17-state program area.

Chlorantraniliprole will not be considered for use in Nevada during the 2020 treatment 

season. With the incorporation and use of application buffers and other operational 

procedures APHIS anticipates that any impacts associated with the use and fate of 

program insecticides will be insignificant and discountable to listed species and their 

habitats. Based on an assessment of the potential exposure, response, and subsequent risk

characterization of program operations, APHIS concludes the proposed action is not 

likely to adversely affect listed species or critical habitat in the program area. APHIS has 

requested concurrence from the USFWS on these determinations. Until this 

programmatic Section 7 consultation with USFWS is completed, APHIS will conduct 

consultations with USFWS field offices at the local level.

APHIS personnel has been conferring with the U.S. Fish and Wildlife Service, Nevada 

Fish and Wildlife Office to discuss section 7 consultations as required by the Endangered 

Species Act of 1973 annually since 2007. On June 25 2018, USFWS provided a letter of 

concurrence to APHIS personnel for the 2018, 2019, and 2020 treatment seasons. 

Included in Appendix C is the U.S. Fish and Wildlife Service listing of Nevada 

endangered, threatened, proposed, and candidate species (Table 1). 

The 1995 biological opinion issued by USFWS lists the mitigations to be followed by 

APHIS when conducting a suppression program to control grasshoppers with insecticides 

other than diflubenzuron. This list is included in Appendix C (Table 2). Mitigation 

measures for use of malathion and carbaryl for new listings (since 1995) of threatened, 

endangered and proposed species that have not been included in formal Section 7 

consultation are also included in Appendix C (Table 3). Mitigation measures as required 

by USFWS for threatened, endangered, and proposed species incorporating the use of 

diflubenzuron on grasshopper suppression programs are included in Table 3. 
35

APHIS is not required to develop mitigation buffer zones for candidate or other species 

of concern. The Columbia spotted frog (Great Basin population) (Rana luteiventris) and 

Greater Sage Grouse are species of concern and located within our proposed treatment

areas for 2020. However, species of concern receive no legal protection under the Act, 

but consideration of these species will be discusses with the local land managers prior to 

any treatments to assist in conservation efforts. Agreed upon mitigation measures 

between USFWS, NDOW, NDA, and APHIS will be followed. Yearly local program 

consultations with the requesting agency would determine if mitigation measures would 

allow a suppression program to be done. 

7. Bald and Golden Eagle Protection Act

The Bald and Golden Eagle Protection Act (16 U.S.C. 668–668c) prohibits anyone, 

without a permit issued by the Secretary of the Interior, from “taking” bald eagles, 

including their parts, nests, or eggs. During the breeding season, bald eagles are sensitive 

to a variety of human activities. Grasshopper management activities could cause 

disturbance of nesting eagles, depending on the duration, noise levels, extent of the area 

affected by the activity, prior experiences that eagles have with humans, and tolerance of 

the individual nesting pair. Also, disruptive activities in or near eagle foraging areas can 

interfere with bald eagle feeding, reducing chances of survival. USFWS has provided 

recommendations for avoiding disturbance at foraging areas and communal roost sites 

that are applicable to grasshopper management programs (USFWS, 2007).

No toxic effects are anticipated on eagles as a direct consequence of insecticide 

treatments. Toxic effects on the principle food source, fish, are not expected because 

insecticide treatments will not be conducted over rivers or lakes. Buffers protective of 

aquatic biota are applied to their habitats to ensure that there are no indirect effects from 

loss of prey.

8. Additional Species of Concern

There may be species that are of special concern to land management agencies, the 

public, or other groups and individuals in proposed treatment areas. For example, the 

sage grouse populations have declined throughout most of their entire range, with habitat 

loss being a major factor in their decline.

Grasshopper suppression programs reduce grasshoppers and at least some other insects in 

the treatment area that can be a food item for sage grouse chicks. As indicated in previous 

sections on impacts to birds, there is low potential that the program insecticides would be 

toxic to sage grouse, either by direct exposure to the insecticides or indirectly through 

immature sage grouse eating moribund grasshoppers. 

Because grasshopper numbers are so high in an outbreak year, treatments would not 

likely reduce the number of grasshoppers below levels present in a normal year. Should 

grasshoppers be unavailable in small, localized areas, sage grouse chicks may consume 

other insects, which sage grouse chicks likely do in years when grasshopper numbers are 

naturally low. By suppressing grasshoppers, rangeland vegetation is available for use by 

other species, including sage grouse, and rangeland areas are less susceptible to invasive 

plants that may be undesirable for sage grouse habitat.
36

Through an agreement between Nevada Department of Agriculture (NDA), Nevada 

Department of Wildlife (NDOW), USDA Plant Protection and Quarantine (PPQ), the 

Bureau of Land Management (BLM), and the United Stated Fish and Wildlife Service 

(USFWS) all parties agree to limit the use of insecticides within sage-grouse habitat for 

grasshopper and Mormon cricket control during times that would have the greatest 

chance of disturbing sage-grouse during critical nesting and brooding periods. For aerial 

applications of Dimilin, no applications will occur within three miles of active and 

pending sage grouse leks during the intervals of one hour before sunrise to two hours 

after sunrise, and from two hours before sunset to one hour after sunset. 

Ground applications will use specially formulated carbaryl baits to mitigate potential 

impacts to non-target species. No carbaryl bait will be applied within three miles of any 

active or pending sage grouse lek. Through consultation with NDOW and BLM, areas 

where crops, roads, or urban areas are to be protected, two track or other categories of 

roads may be utilized to distribute carbaryl bait within the sage grouse buffer zone, up to 

one mile from the area to be protected. If a lek is found within one mile from the 

protected area, further consultation will be had with NDOW and USFWS. Any ground 

baiting activity approved by NDOW and USFWS within the sage grouse buffer zone 

using carbaryl bait would also comply with the time frame constraints consistent with 

that of the aerial applications of Dimilin. 

There are also biocontrol programs established by various land managers as well as 

county, state, and federal agencies. Nevada Department of Agriculture (NDA) works in 

conjunction with APHIS personnel through a cooperative agreement. NDA also 

maintains a healthy biocontrol program. All biocontrol sites are mapped and logged for 

relocation purposes. If a biocontrol site overlapped with a proposed treatment, APHIS 

and NDA would agree upon mitigation measures prior to beginning treatment. 

Biocontrol populations established by other land managers would be the responsibility of 

the land manager to identify to APHIS personnel during site specific consultation 

between APHIS and the land manager. 

9. Fires and Human Health Hazards

Various compounds are released in smoke during wildland fires, including carbon 

monoxide (CO), carbon dioxide, nitrous oxides, sulfur dioxide, hydrogen chloride, 

aerosols, polynuclear aromatic hydrocarbons contained within fine particulate matter (a 

byproduct of the combustion of organic matter such as wood), aldehydes, and most 

notably formaldehyde produced from the incomplete combustion of burning biomass

(Reisen and Brown, 2009; Burling et al., 2010; Broyles, 2013). Particulate matter, CO, 

benzene, acrolein, and formaldehyde have been identified as compounds of particular 

concern in wildland fire smoke (Reinhardt and Ottmar, 2004). 

Many of the naturally occurring products associated with combustion from wildfires may 

also be present as a result of combustion of program insecticides that are applied to 

rangeland. These combustion byproducts will be at lower quantities due to the short halflives of most of the program insecticides and their low use rates. Other minor combustion 

products specific to each insecticide may also be present as a result of combustion from a 
37

rangeland fire but these are typically less toxic based on available human health data 

(http://www.aphis.usda.gov/plant-health/grasshopper).

The safety data sheet (SDS) for each insecticide identifies these combustion products for 

each insecticide as well as recommendations for PPE. The PPE is similar to what 

typically is used in fighting wildfires. Material applied in the field will be at a much 

lower concentration than what would occur in a fire involving a concentrated 

formulation. Therefore the PPE worn by rangeland firefighters would also be protective 

of any additional exposure resulting from the burning of residual insecticides. 

10. Cultural and Historical Resources

Federal actions must seek to avoid, minimize, and mitigate potential negative impacts to 

cultural and historic resources as part of compliance with the National Historic 

Preservation Act (NHPA), the Archaeological Resources Protection Act of 1979, and 

NEPA. Section 106 of the NHPA requires Federal agencies to provide the Advisory 

Council on Historic Preservation with an opportunity to comment on their findings.

Consultation with the appropriate landowner, State Historic Preservation Office, National 

Trail’s administrative office, or other appropriate agencies will be conducted when 

appropriate to ensure minimal impacts to cultural and historical resources in the proposed 

treatment areas. 

V. Literature Cited

Bavcon, M., Trebse, P., and L. Zupancic-Kralj. 2005. Investigations of the determination 

and transformations of diazinon and malathion under environmental conditions 

using gas chromatography coupled with a flam ionization detector. Chemosphere. 

50: 595–601. 

Beauvais, S. 2014. Human exposure assessment document for carbaryl. Page 136. 

California Environmental Protection Agency, Department of Pesticide 

Regulation.

Belovsky, G. E., A. Joern, and J. Lockwood. 1996. VII.16 Grasshoppers—Plus and 

Minus: The Grasshopper Problem on a Regional Basis and a Look at Beneficial 

Effects of Grasshoppers. Pages 1-5 in G. L. Cunningham and M. W. Sampson, 

editors. Grasshopper Integrated Pest Management User Handbook, Technical 

Bulletin No. 1809. U.S. Department of Agriculture, Animal and Plant Health 

Inspection Service, Washington, DC.

Belovsky, G. E. 2000. Part 1. Grasshoppers as integral elements of grasslands. 1. Do 

grasshoppers diminish grassland productivity? A new perspective for control 

based on conservation. Pages 7-29 in J. A. Lockwood et al, editor. Grasshoppers 

and Grassland Health. Kluwer Academic Publishers, Netherlands.

Bonderenko, S., J. Gan, D. L. Haver, and J. N. Kabashima. 2004. Persistence of selected 

organophophate and carbamate insecticides in waters from coastal watershed. 

Env. Toxicol. Chem. 23:2649-2654.

Bradshaw, J. D., K. H. Jenkins, and S. D. Whipple. 2018. Impact of grasshopper control 

on forage quality and availability in western Nebraska. Rangelands 40:71-76.
38

Branson, D., A. Joern, and G. Sword. 2006. Sustainable management of insect herbivores 

in grassland ecosystems: new perspectives in grasshopper control. BioScience 

56:743-755.

Broyles, G. 2013. Wildland firefighter smoke exposure. Page 26. U.S. Department of 

Agriculture, Forest Service.

Buckner, C. H., P. D. Kingsbury, B. B. McLeod, K. L. Mortensen, and D. G. H. Ray. 

1973. The effects of pesticides on small forest vertebrates of the spruce woods 

provincial forest, Manitoba. The Manitoba Entomologist 7:37-45.

Burling, I., R. Yokelson, D. Griffith, T. Johson, P. Veres, J. Roberts, C. Warneke, S. 

Urbanski, J. Reardon, D. Weise, W. Hao, and J. de Gouw. 2010. Laboratory 

measures of trace gas emissions from biomass burning of fuel types from the 

southeastern and southwestern United States. Atmospheric Chemistry and Physics 

10:11115-111130.

California Department of Pesticide Regulations (CDPR). 1993. Assessment of Malathion 

and Malaoxon concentration and persistence in water, plant, soil, and plant 

matrices under controlled exposure experiments by Rosemary H. Neal, Patrick 

M. Mccool, Theodore Younglove. University of 

California, https://www.cdpr.ca.gov/

Capowiez, Y., Y. A. Bérard, 2006. Assessment of the effects of imidacloprid on the 

behavior of two earthworm species 

(Aporrectodea nocturna and Allolobophora icterica) using 2D terraria. Ecotox. 

Environ. Saf., 64 (2006), pp. 198-206.  

Caro, J. H., H. P. Freeman, and B. C. Turner. 1974. Persistence in soil and losses in 

runoff of soil-incorporated carbaryl in a small watershed. J. Agricul. Food Chem. 

22:860-863.

Catangui, M.A., Fuller, B.W., and Walz, A.W., 1996. Impact of Dimilin® on nontarget 

arthropods and its efficacy against rangeland grasshoppers. In U.S. Department 

of Agriculture, Animal and Plant Health Inspection Service, 1996. Grasshopper 

Integrated Pest Management User Handbook, Tech. Bul. No. 1809. Sec. VII.3. 

Washington, DC.

Cooper, R. J., K. M. Dodge, P. J. Marinat, S. B. Donahoe, and R. C. Whitmore. 1990. 

Effect of diflubenzuron application on eastern deciduous forest birds. J. Wildl. 

Mgmt. 54:486-493.

Cordova, D., E. Benner, M. D. Sacher, J. J. Rauh, J. S. Sopa, G. Lahm, T. Selby, T. 

Stevenson, L. Flexner, S. Gutteridge, D. F. Rhoades, L. Wu, R. M. Smith, and Y. 

Tao. 2006. Anthranilic diamides: a new class of insecticides with a novel mode of 

action, ryanodine receptor activation. Pesticide Biochemistry and Physiology 

84:196-214.

Davis, B.N.K., 1971. Laboratory studies on the uptake of dieldrin and DDT by 

earthworms. Soil Biol. Biochem. 3, 221–223.  

Deakle, J. P. and J. R. Bradley, Jr. 1982. Effects of early season applications of 

diflubenzuron and azinphosmethyl on populations levels of certain arthropods in 

cotton fields. J. Georgia Entomol. Soc. 17:189-200.

Deneke, D. and J. Keyser. 2011. Integrated Pest Management Strategies for Grasshopper 

Management in South Dakota. South Dakota State University Extension.
39

Dinkins, M. F., A. L. Zimmermann, J. A. Dechant, B. D. Parkins, D. H. Johnson, L. D. 

Igl, C. M. Goldade, and B. R. Euliss. 2002. Effects of Management Practices on 

Grassland Birds: Horned Lark Northern Prairie Wildlife Research Center. Page 

34. Northern Prairie Wildlife Research Center, Jamestown, ND.

Dobroski, C. J., E. J. O'Neill, J. M. Donohue, and W. H. Curley. 1985. Carbaryl: a profile 

of its behaviors in the environment. Roy F. Weston, Inc. and V.J. Ciccone and 

Assoc., Inc., West Chester, PA; Woodbridge, VA.

Eisler, R. 1992. Diflubenzuron Hazards to Fish, Wildlife, and Invertebrate: A Synoptic 

Review. U.S. Department of Interior, Fish and Wildlife Service, Washington, 

D.C.

Eisler, R., 2000. Handbook of chemical risk assessment: health hazards to humans, 

plants, and animals. Lewis Publishers, New York.

El-Refai, A. and T. L. Hopkins. 1972. Malathion adsorption, translocation, and 

conversion to malaoxon in bean plants. J. Assoc. Official Analytical Chemists 

55:526-531.

Fischer, S. A. and L. W. Hall, Jr. 1992. Environmental concentrations and aquatic 

toxicity data on diflubenzuron (Dimilin). Critical Rev. in Toxicol. 22:45-79.

FMC. 2019. Appendix D. Ecological Study Evaluation and End Points for Tier 1 Risk 

Assessments. Cheminova’s Ecotoxicological Study Evaluation Criteria, Study 

Evaluations and Proposed Screening-Level Effects Metrics for Registration 

Review of Malathion. March 4, 2014.

Follett, R. F. and D. A. Reed. 2010. Soil carbon sequestration in grazing lands: societal 

benefits and policy implications. Rangeland Ecology & Management 63:4-15.

Foster, R. N., K. C. Reuter, K. Fridley, D. Kurtenback, R. Flakus, R. Bohls, B. Radsick, 

J. B. Helbig, A. Wagner, and L. Jeck. 2000. Field and Economic Evaluation of 

Operational Scale Reduced Agent and Reduced Area Treatments (RAATs) for 

Management of Grasshoppers in South Dakota Rangeland. U.S. Department of 

Agriculture, Animal and Plant Health Inspection Service, Plant Protection and 

Quarantine, Phoenix, AZ.

George, T. L., L. C. McEwen, and B. E. Peterson. 1995. Effects of grasshopper control 

programs on rangeland breeding bird populations. J. Range Manage. 48:336–342.

Gramlich, F. J. 1979. Effects of Sevin on songbird cholinesterase. Environmental 

Monitoring of Cooperative Spruce Budworm Control Projects. Maine Department 

of Conservation, Bureau of Forestry, Augusta, ME.

Greenberg, J. and Q.N. LaHam. Malathion-induced teratisms in the developing chick. 

Canadian Journal of Zoology, 47 (1969), pp. 539-542 

Guerrant, G. O., L. E. Fetzer, Jr., and J. W. Miles. 1970. Pesticide residues in Hale 

County, Texas, before and after ultra-low-volume aerial applications of 

Malathion. Pesticide Monitoring J. 4:14-20.

Hansen, R. W. & E. A. Osgood. 1984. Effects of a split application of sevin-4-oil on 

pollinators and fruit set in in a spruce-fir forest. Can. Entomol. 116: 457-464.  

Havstad, K. M., D. P. Peters, R. Skaggs, J. Brown, B. Bestelmeyer, E. Fredrickson, J. 

Herrick, and J. Wright. 2007. Ecological services to and from rangelands of the 

United States. Ecological Economics 64:261-268.

Helson, B. V., Barber, K. N., & Kingsbury, P. D. 1994. Laboratory toxicology of six 

forestry insecticides to four species of bee (hymenoptera: Apoidea). Archives of 
40

Environmental Contamination and Toxicology, 

27(1). https://doi.org/10.1007/BF00203895.  

Hoffman, D.J.  Eastin, W.C. 1981. Effects of malathion, diazinon, and parathion on 

mallard embryo development and cholinesterase activity. Environ Res.  Dec, 

26(2):472-85.

Howe, F. P. 1993. Effects of Grasshopper Insecticide Application on Diet, Food Delivery 

Rates, Growth, and Survival of Shrubsteppe Passarine. Page 108 PhD dissertation. 

Colorado State University, Fort Collins, CO.

Howe, F. P., R. L. Knight, L. C. McEwen, and T. L. George. 1996. Direct and indirect 

effects of insecticide applications on growth and survival of nestling passerines. 

Ecol. Appl. 6:1314-1324.

Johansen, C. A., D. F. Mayer, J. D. Eves, and C. W. Kious. 1983. Pesticides and bees. 

Environ. Entomol. 12: 1513-1518.  

Joy, V. C., & Chakravorty, P. P. 1991. Impact of insecticides on nontarget 

microarthropod fauna in agricultural soil. Ecotoxicology and Environmental 

Safety, 22(1), 8–16. https://doi.org/10.1016/0147-6513(91)90041-M.  

Kar, A., K. Mandal, and B. Singh. 2012. Environmental fate of cholorantraniliprole 

residues on cauliflower using QuEChERS technique. Environ. Monit. Assess 

85:1255-1263.

Keever, D. W., J. R. Bradley, Jr, and M. C. Ganyard. 1977. Effects of diflubenzuron 

(Dimilin) on selected beneficial arhropods in cotton fields. J. Econ. Entomol. 

6:832-836.

LaFleur, K. S. 1979. Sorption of pesticides by model soils and agronomic soils: rates and 

equilibria. Soil Sci. 127:94-101.

Larsen, J. and R. N. Foster. 1996. Using Hopper to Adapt Treatments and Costs to Needs 

and Resources. U.S. Department of Agriculture, Animal and Plant Health 

Inspection Service Grasshopper Integrated Pest Management User Handbook, 

Washington, D.C.

Larson, J. L., C. T. Redmond, and D. A. Potter. 2012. Comparative impact of an 

antrhanilic diamide and other insecticidal chemistries on beneficial invertebrates 

and ecosystem services in turfgrass. Pest Management Science 68(5), 740–

748. https://doi.org/10.1002/ps.2321.  

Latchininsky, A., G. Sword, M. Sergeev, M. Cigiliano, and M. Lecoq. 2011. Locusts and 

grasshoppers: behavior, ecology, and biogeography. Psyche 2011:1-4.

Lima, M. P. R., Soares, A. M. V. M., & Loureiro, S. 2011. Combined effects of soil 

moisture and carbaryl to earthworms and plants: Simulation of flood and drought 

scenarios. Environmental Pollution, 159(7), 1844–

1851. https://doi.org/10.1016/j.envpol.2011.03.029.  

Lillie, R.J. 1973. Studies on the reproductive performance and progeny performance of 

caged White Leghorns fed malathion and carbaryl. Poult Sci. Jan, 52(1):266-72.

Lockwood, J. A. and S. P. Schell. 1997. Decreasing economic and environmental costs 

through reduced area and agent insecticide treatments (RAATs) for the control of 

rangeland grasshoppers: empirical results and their implications for pest 

management. J. Orthoptera Res. 6:19-32.
41

Lockwood, J.A., S.P. Schell, R.N. Foster, C. Reuter, and T. Rachadi.1999. Reduced 

agent-area treatments (RAATs) for management of rangeland grasshoppers: 

efficacy and economics under operational conditions. Int. J. Pest Manage. 46:29-

42.  

Lockwood, J.A., Narisu, S.P. Schell, and D.R. Lockwood. 2001. Canola oil as 

a kairomonal attractant of rangeland grasshoppers (Orthoptera: Acrididae): an 

economical liquid bait for insecticide formulation. Int. J. Pest Manage. 47:185–

194.  

Lockwood, J.A., R. Anderson-Sprecher, and S.P. Schell. 2002. When less is more: 

optimization of reduced agent-area treatments (RAATs) for management of 

rangeland grasshoppers. Crop Protection. 21:551-562.  

Lockwood, J., S. Schell, R. Foster, C. Reuter, and T. Rahadi. 2000. Reduced agent-area 

treatments (RAAT) for management of rangeland grasshoppers: efficacy and 

economics under operational conditions. International Journal of Pest 

Management 46:29-42.

Lockwood, J. A. and A. Latchininsky. 2000. The Risks of Grasshoppers and Pest 

Management to Grassland Agroecosystems: An International Perspective on 

Human Well-Being and Environmental Health. Pages 193-215 in A. Latchininsky 

and M. Sergeev, editors. Grasshoppers and Grassland Health. Kluwer Academic 

Publishers.

Lockwood, J., R. Anderson-Sprecher, and S. Schell. 2002. When less is more: 

optimization of reduced agent-area treatments (RAATs) for management of 

rangeland grasshoppers. Crop Protection 21:551-562.

Malhat, F., H. Adbdallah, and I. Hegazy. 2012. Dissipation of chlorantraniliprole in 

tomato fruits and soil. Bul. Environ. Contam. Toxicol. 88:349-351.

Matsumara, F. 1985. Toxicology of insecticides. Plenum Press, New York.

McEwen, L.C., Althouse, C.M., and Peterson, B.E., 1996. Direct and indirect effects of 

grasshopper integrated pest management (GHIPM) chemicals and biologicals on 

nontarget animal life. In U.S. Department of Agriculture, Animal and Plant 

Health Inspection Service, 1996. Grasshopper Integrated Pest Management User 

Handbook, Tech. Bul. No. 1809. Sec. III.2. Washington, DC.

Miles, C. J. and S. Takashima. 1991. Fate of malathion and O.O.S. trimethyl 

phosphorothioate byproduct in Hawaiian soil and water. Arch. Environ. Contam. 

Toxicol 20:325-329.

Murphy, C. F., P. C. Jepson, and B. A. Croft. 1994. Database analysis of the toxicity of 

antilocust pesticides to non-target, beneficial invertebrates. Crop Protection 

13:413-420.

Muzzarelli, R. 1986. Chitin synthesis inhibitors: effects on insects and on nontarget 

organisms. CRC Critical Review of Envionmental Control 16:141-146.

Narisu, J., A. Lockwood, and S. P. Schell. 1999. A novel mark-capture technique and its 

application to monitoring the direction and distance of local movements of 

rangeland grasshoppers (Orthoptera: Acridade) in context of pest management. J. 

Appl. Ecol. 36:604-617.

Narisu, J., A. Lockwood, and S. P. Schell. 2000. Rangeland grasshopper movement as a 

function of wind and topography: implications for pest movement. J. Appl. Ecol. 

36:604-617.
42

Neary, D. G. 1985. Fate of pesticides in Florida's forests: an overview of potential 

impacts of water quality. Pages 18-24 in Procs. Soil and Crop Sci. Soc. of FL.

Nigg, H. N., R. D. Cannizzaro, and J. H. Stamper. 1986. Diflubenzuron surface residues 

in Florida citrus. Bul. Environ. Contam. Toxicol. 36:833-838.

NIH. 2009a. Carbaryl, CASRN: 63-25-2. National Institutes of Health, U.S. National 

Library of Medicine, Toxnet, Hazardous Substances Database.

NIH. 2009b. National Institutes of Health, U.S. National Library of Medicine, Hazardous 

Substances Database.

Norelius, E. E. and J. A. Lockwood. 1999. The effects of reduced agent-area insecticide 

treatments for rangeland grasshopper (Orthoptera: Acrididae) control on bird 

densities. Archives of Environmental Contamination and Toxicology 37:519-528.

Norelius, E.E. and J.A. Lockwood. 1999. The effects of standard and reduced agent-area 

insecticide treatments for rangeland grasshopper (Orthoptera: Acrididae) control 

on bird densities. Arch. Environ. Toxicol. 37:519–528.  

Panda, S., & Sahu, S. K. 2004. Recovery of acetylcholine esterase activity 

of Drawida willsi (Oligochaeta) following application of three pesticides to soil. 

Chemosphere, 55(2), 283–290.  

Pascual, J. A. 1994. No effects of a forest spraying of malathion on breeding blue tits 

(Parus caeruleus). Environ. Toxicol. Chem. 13:1127–1131.

Peach, M. P., D. G. Alston, and V. J. Tepedino. 1994. Bees and bran bait: is carbaryl bran 

bait lethal to alfalfa leafcutting bee (Hymenoptera: Megachilidae) adults or 

larvae? J. Econ. Entomol. 87:311-317.

Peach, M. P., D. G. Alston, and V. J. Tepedino. 1995. Subleathal effects of carbaryl bran 

bait on nesting performance, parental investment, and offspring size and sex ratio 

of the alfalfa leafcutting bee (Hymenoptera: Megachilidae). Environ. Entomol. 

24:34-39.

Pfadt, R. E. 1994. Field Guide to Common Western Grasshoppers. Wyoming 

Agricultural Experiment Station Bulletin 912. Wyoming Agricultural Experiment 

Station.  

Pfadt, R. E. 2002. Field Guide to Common Western Grasshoppers, Third Edition. 

Wyoming Agricultural Experiment Station Bulletin 912. Laramie, Wyoming.

Potter, D. A., Buxton, M. C., Redmond, C. T., Patterson, C. G., & Powell, A. J. 

1990. Toxicity of Pesticides to Earthworms (Oligochaeta: Lumbricidae) and 

Effect on Thatch Degradation in Kentucky Bluegrass Turf. Journal of Economic 

Entomology, 83(6), 2362–2369. https://doi.org/10.1093/jee/83.6.2362.  

Purdue University. 2018. National Pesticide Information Retrieval System. West 

Lafayette, IN.

Quinn, M.A. 2000. North Dakota Integrated Pest Management Demonstration Project, 

Technical Bulletin No. 1891. Page 124 pp. U.S. Department of Agriculture, 

Animal and Plant Health Inspection Service, Washington D.C. 

Quinn, M. A., R. L. Kepner, D. D. Walgenbach, R. N. Foster, R. A. Bohls, P. D. Pooler, 

K. C. Reuter, and J. L. Swain. 1991. Effect of habitat and perturbation on 

populations and community structure of darkling beetles (Coleoptera: 

tenebrionidae) on mixed grass rangeland. Environ. Entomol. 19:1746-1755.
43

Rashford, B. S., A. V. Latchininsky, and J. P. Ritten. 2012. An Economic Analysis of the 

Comprehensive Uses of Western Rangelands. U.S. Department of Agriculture, 

Animal and Plant Health Inspection Service.

Reinhardt, T. and R. Ottmar. 2004. Baseline measurements of smoke exposure among 

wildland firefighters. Journal of Occupational and Environmental Hygiene 1:593-

606.

Reisen, F. and S. Brown. 2009. Australian firefighters' exposure to air toxics during 

bushfire burns of autumn 2005 and 2006. Environment International 35:342-353.

Richmond, M. L., C. J. Henny, R. L. Floyd, R. W. Mannan, D. W. Finch, and L. R. 

DeWeese. 1979. Effects of Sevin 4-oil, Dimilin, and Orthene on Forest Birds in 

Northeastern Oregon. USDA, Pacific SW Forest and Range Experiment Station.

Rosenberg, K. V., R. D. Ohmart, and B. W. Anderson. 1982. Community organizaion of 

riparian breeding birds: response to an annual resource peak. The Auk 99:260-

274.

Sample, B. E., R. J. Cooper, and R. C. Whitmore. 1993. Dietary shifts among songbirds 

from a diflubenzuron-treated forest. The Condor 95:616-624.

Sanchez-Hernandez, J.C. 2006. Earthworms Biomarkers in Ecological Risk Assessment. 

In; Ware, G.W., et al., Eds., Reviews of Environmental Contamination and 

Toxicology, Springer, New York, 85-126.http://dx.doi.org/10.1007/978-0-387-

32964-2_3

Schaefer, C. H., A. E. Colwell, and E. F. Dupras, Jr. 1980. The occurrence of pchloroaniline and p-c hlorophenylurea from the degradation of pesticide in water 

and fish. Proceedings of the 48th Ann. Meeting Mosquito Vector Cont. 

Assoc.:84-89.

Schaefer, C. H. and E. F. Dupras, Jr. 1977. Residues of diflubenzuron [1-(4-

chlorophenyl)-3(2,6-difluorobenzoyl) urea] in pasture soil, vegetation, and water 

following aerial applications. J. Agric. Food Chem. 25:1026-1030.

Schroeder. W.J., R. A. Sutton, and J. B. Beavers, 1980. Diaprepes abbreviatus: Fate of 

Diflubenzuron and Effect on Nontarget Pests and Beneficial Species after 

Application to Citrus for Weevil Control, Journal of Economic 

Entomology. 73(5):637–638. https://doi.org/10.1093/jee/73.5.637  

Smith, D. and J. Lockwood. 2003. Horizontal and trophic transfer of diflubenzuron and 

fipronil among grasshoppers and between grasshoppers and darkling beetles 

(Tenebrionidae). Archives of Environmental Contamination and Toxicology 

44:377-382.

Smith, D. I., J. A. Lockwood, A. V. Latchininsky, and D. E. Legg. 2006. Changes in nontarget populations following applications of liquid bait formulations of 

insecticides for control of rangeland grasshoppers. Internat. J. Pest Mgt. 52:125-

139.

Stanley, J. G. and J. G. Trial. 1980. Disappearance constants of carbaryl from streams 

contaminated by forest spraying. Bul. Environ. Contam. Toxicol. 25:771-776.

Stark, J. D., P. C. Jepson, and D. F. Mayer. 1995. Limitations to use of topical toxicity 

data for predictions of pesticide side effects in the field. J. Econ. Entomol. 88: 

1081-1088.  

Stepić, S., Hackenberger, B. K., Velki, M., Hackenberger, D. K., & Lončarić, Ž. 

2013. Potentiation Effect of Metolachlor on Toxicity of Organochlorine and 
44

Organophosphate Insecticides in Earthworm Eisenia andrei. Bulletin of 

Environmental Contamination and Toxicology, 91(1), 55–

61. https://doi.org/10.1007/s00128-013-1000-0.   

Stepić, S., Hackenberger, B. K., Velki, M., Lončarić, Ž., & Hackenberger, D. K. 

2013. Effects of individual and binary-combined commercial 

insecticides endosulfan, temephos, malathion and pirimiphos-methyl on biomarker 

responses in earthworm Eisenia andrei. Environmental Toxicology and 

Pharmacology, 36(2), 715–723. https://doi.org/10.1016/j.etap.2013.06.011.  

Swain, J. L. 1986. Effect of Chemical Grasshopper Controls on Non-Target Arthropods 

of Rangeland in Chaves County, New Mexico. New Mexico State University.

Tasei, J. 2001. Effects of insect growth regulators on honey bees and non-Apis bees. A 

review. Apidologie. 32:527-545.   

Tepedino, V. J. 1979. The importance of bees and other insect planetaries in maintaining 

floral species composition. Great Basin Naturalist Memoirs 3:139-150.

Thomson, D. L. K. and W. M. J. Strachan. 1981. Biodegradation of carbaryl in simulated 

aquatic environment. Bul. Environ. Contam. Toxicol. 27:412-417.

Van Gestel, C.A.M., VanDis, W.A., 1988. The influence of soil characteristics on the 

toxicity of four chemicals to earthworm Eisenia andrei (Oligochaeta). Biol. Fertil. 

Soils 6, 262–265.  

USDA APHIS– see U.S. Department of Agriculture, Animal and Plant Health Inspection 

Service

U.S. Department of Agriculture, Animal and Plant Health Inspection Service, 1999. 

APHIS Directive 5600.3, Evaluating APHIS programs and activities for ensuring 

protection of children from environmental health risks and safety risks. 

September 3, 1999. U.S. Department of Agriculture, Animal and Plant Health 

Inspection Service, Riverdale, MD. [online] available: 

http://www.aphis.usda.gov/library/directives.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2015. 

Biological Assessment for the APHIS Rangeland Grasshopper and Mormon 

Cricket Suppression Program. Page 162. U.S. Department of Agriculture, Animal 

and Plant Health Inspection Service.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2016. 

APHIS Rangeland Grasshopper/Mormon Cricket Suppression Program Aerial 

Application, Statement of Work. Page 39 pp. U.S. Department of Agriculture, 

Animal and Plant Health Inspection Service.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2018a. 

Human Health and Ecological Risk Assessment for Carbaryl Rangeland 

Grasshopper and Mormon Cricket Suppression Applications. United States 

Department of Agriculture, Animal and Plant Health Inspection Service.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2018b. 

Human Health and Ecological Risk Assessment for Chlorantraniliprole used in 

the Rangeland Grasshopper and Mormon Cricket Suppression Program. United 

States Department of Agriculture, Animal and Plant Health Inspection Service.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2018c. 

Human Health and Ecological Risk Assessment for Diflubenzuron Rangeland 
45

Grasshopper and Mormon Cricket Suppression Applications. United States 

Department of Agriculture, Animal and Plant Health Inspection Service.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 2018d.

Human Health and Ecological Risk Assessment for Malathion Rangeland 

Grasshopper and Mormon Cricket Suppression Applications. United States 

Department of Agriculture, Animal and Plant Health Inspection Service.

USDA FS. 2004. Control/eradication agents for the gypsy moth—human health and

ecological risk assessment for diflubenzuron (final report). United States 

Department of Agriculture, Forest Service

USDA FS. 2008. Malathion- Human Health and Ecological Risk Assessment. U.S. 

Department of Agriculture, Forest Service.

USEPA – See U.S. Environmental Protection Agency

U.S. Environmental Protection Agency. 1997. Reregistration Eligibility Decision (RED): 

Diflubenzuron. U.S. Environmental Protection Agency.

U.S. Environmental Protection Agency. 2000a. Malathion Reregistration Eligibility 

Document Environmental Fate and Effects. Page 146. U.S. Environmental 

Protection Agency, Office of Prevention, Pesticides and Toxic Substances.

U.S. Environmental Protection Agency. 2000b. Reregistration Eligibility Decision (RED) 

for Malathion. U.S. Environmental Protection Agency.

USEPA. 2003. Environmental Fate and Ecological Risk Assessment for Re-Registration 

of Carbaryl. U.S. Environmental Protection Agency.

U.S. Environmental Protection Agency. 2006. Malathion Reregistration Eligibility 

Document. Page 147. U.S. Environmental Protection Agency, Office of Pesticide 

Programs.

U.S. Environmental Protection Agency. 2007. Reregistration Eligibility Decision (RED) 

for Carbaryl. Page 47. U.S. Environmental Protection Agency, Prevention, 

Pesticides and Toxic Substances.

U.S. Environmental Protection Agency. 2008. Pesticide Fact Sheet: Chlorantraniliprole. 

Page 77. U.S. Environmental Protection Agency, Office of Prevention, Pesticides 

and Toxic Substances.

U.S. Environmental Protection Agency. 2012. Ecotox database accessed 

at: http://cfpub.epa.gov/ecotox/

U.S. Environmental Protection Agency. 2012a. Fyfanon ULV AG. U.S. Environmental 

Protection Agency.

U.S. Environmental Protection Agency. 2012b. Memorandum, Chlorantraniliprole: 

human health risk assessment for proposed uses on oilseeds (Subgroups 20A 

through C) and soybean (Crop group 6 and 7). U.S. Environmental Protection 

Agency.

U.S. Environmental Protection Agency. 2012c. Sevin XLR Plus Label. Pages 1-40

Pesticide Product and Label System. U.S. Environmental Protection Agency.

U.S. Environmental Protection Agency. 2015a. Annual Cancer Report 2015, Chemicals 

Evaluated for Carcinogenic Potential Page 34. U.S. Environmental Protection 

Agency, Office of Pesticide Programs.

U.S. Environmental Protection Agency. 2015b. Memorandum - Diflubenzuron: human 

health risk assessment for an amended Section 3 registration for carrot, peach 

subgroup 12-12B, plum subgroup 12-12C, pepper/eggplant subgroup 8010B, 
46

cottonseed subgroup 20C, alfalfa (regional restrictions) and R175 Crop Group 

Conversion for tree nut group 14-12. Page 71 U.S. Environmental Protection 

Agency, Office of Pesticide Programs.

U.S. Environmental Protection Agency. 2016a. Appendix 3-1: Environmental transport 

and fate data analysis for malathion. In: Biological Evaluation Chapters for 

Malathion ESA Assessment.

U.S. Environmental Protection Agency. 2016b. Chapter 2: Malathion Effects 

Characterization for ESA Assessment. In: Biological Evaluation Chapters for 

Malathion ESA Assessment.

U.S. Environmental Protection Agency. 2016c. Malathion: Human Health Draft Risk 

Assessment for Registration Review. Page 258. U.S. Environmental Protection 

Agency.

U.S. Environmental Protection Agency. 2017a. Memorandum - Carbaryl: Draft Human 

Health Risk Assessment in Support of Registration Review. Page 113 U.S. 

Environmental Protection Agency.

U.S. Environmental Protection Agency. 2017b. Prevathon Label. U.S. Environmental 

Protection Agency.

U.S. Environmental Protection Agency. 2018. Preliminary Risk Assessment to Support 

the Registration Review of Diflubenzuron.

USFWS. 2007. National Bald Eagle Management Guidelines. Page 23 pp. U.S. Fish and 

Wildlife Service.

USFWS. 2007. Recommended Protection Measures for Pesticide Applications in Region 

2 of the U.S. Fish and Wildlife Service. 

205pp. https://www.fws.gov/southwest/es/arizona/documents/ecreports/rpmpa_20

07.pdf

Wakeland, C. and W. E. Shull. 1936. The Mormon cricket with suggestions for its 

control, Extension Bulletin No. 100. University of Idaho, College of Agriculture, 

Idaho Agricultural Extension.

Zinkl, J. G., C. J. Henny, and L. R. DeWeese. 1977. Brain cholinesterase activities of 

birds from forests sprayed with trichlorfon (Dylox) and carbaryl (Sevin 4-oil). 

Bul. Environ. Contam. Toxicol. 17:379-386.
47

VI. Listing of Agencies and Persons Consulted 

Nevada Department of Agriculture

Jeff Knight (State Entomologist)

405 South 21st St.

Sparks, NV 89431

Nevada Department of Wildlife

Native Aquatic Species Coordinator*

1100 Valley Road

Reno, NV 89512

U.S. Fish and Wildlife Service

Nevada Fish and Wildlife Service

Lee Ann Carranza (Field Supervisor)

Andy Starostka (Fish Biologist) 

Tara Vogel (Fish and Wildlife Biologist)

Edward Koch*

Todd Gilmore*

Kerensa King*

Chad Mellison*

Marcy Haworth*

1340 Financial Blvd. Suite 234

Reno, NV 89502

Bureau of Land Management

Mark Coca*

Vegetation Management Specialist

1340 Financial Blvd.

Reno, NV 89502

US Forest Service

Dirk Netz (Forest Botanist/Invasive Plant 

Program Supervisor)

Meagan Carter (Invasive Plant Program 

manager)

Randall Sharp*

Humboldt-Toiyabe National Forest

1200 Franklin Way

Sparks, NV 89431

USDA APHIS PPQ

Bill Wesela (National Grasshopper Program 

Manager)

Jim Warren (Environmental protection 

Specialist)

Kai Caraher (Biological Scientist)

Charles Brown*

4700 River Road

Riverdale, MD 20737

Nevada Natural Heritage Program

Dept. of Conservation and Natural 

Resources

Eric S. Miskow

Biologist III/ Data Manager

901 South Stewart St., Suite 5002

Carson City, NV 89706-5245

*Indicates past consultation

 

 

 
48

Appendix A

APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program

FY-2020 Treatment Guidelines

Version 02/21/2020

The objectives of the APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program 

are to 1) conduct surveys in the Western States; 2) provide technical assistance to land managers 

and private landowners; and 3) when funds permit, suppress economically damaging grasshopper 

and Mormon cricket outbreaks on Federal, Tribal, State, and/or private rangeland. The Plant 

Protection Act of 2000 provides APHIS the authority to take these actions.

General Guidelines for Grasshopper / Mormon Cricket Treatments

1) All treatments must be in accordance with:

a) the Plant Protection Act of 2000;

b) applicable environmental laws and policies such as: the National Environmental 

Policy Act, the Endangered Species Act, the Federal Insecticide, Fungicide, and 

Rodenticide Act, and the Clean Water Act (including National Pollutant Discharge 

Elimination System requirements – if applicable);

c) applicable state laws;

d) APHIS Directives pertaining to the proposed action;

e) Memoranda of Understanding with other Federal agencies.

2) Subject to the availability of funds, upon request of the administering agency, the 

agriculture department of an affected State, or private landowners, APHIS, to protect 

rangeland, shall immediately treat Federal, Tribal, State, or private lands that are infested 

with grasshoppers or Mormon crickets at levels of economic infestation, unless APHIS 

determines that delaying treatment will not cause greater economic damage to adjacent 

owners of rangeland. In carrying out this section, APHIS shall work in conjunction with 

other Federal, State, Tribal, and private prevention, control, or suppression efforts to 

protect rangeland.

3) Prior to the treatment season, conduct meetings or provide guidance that allows for public 

participation in the decision making process. In addition, notify Federal, State and Tribal 

land managers and private landowners of the potential for grasshopper and Mormon 

cricket outbreaks on their lands. Request that the land manager / land owner advise APHIS 

of any sensitive sites that may exist in the proposed treatment areas.

4) Consultation with local Tribal representatives will take place prior to treatment programs 

to fully inform the Tribes of possible actions APHIS may take on Tribal lands.

5) On APHIS run suppression programs, the Federal government will bear the cost of 

treatment up to 100 percent on Federal and Tribal Trust land, 50 percent of the cost on 

State land, and 33 percent of cost on private land. There is an additional 16.15% charge, 

however, on any funds received by APHIS for federal involvement with suppression 

treatments.

6) Land managers are responsible for the overall management of rangeland under their 

control to prevent or reduce the severity of grasshopper and Mormon cricket outbreaks. 

Land managers are encouraged to have implemented Integrated Pest Management
Appendix A

49

Systems prior to requesting a treatment. In the absence of available funding or in the place of 

APHIS funding, the Federal land management agency, Tribal authority or other party/ies may

opt to reimburse APHIS for suppression treatments. Interagency agreements or reimbursement 

agreements must be completed prior to the start of treatments which will be charged thereto.

7) There are situations where APHIS may be requested to treat rangeland that also includes small 

areas where crops are being grown (typically less than 10 percent of the treatment area). In 

those situations, the crop owner pays the entire treatment costs on the croplands.

NOTE: The insecticide being considered must be labeled for the included crop as well as 

rangeland and current Worker Protection Standards must be followed by the applicator and 

private landowner.

8) In some cases, rangeland treatments may be conducted by other federal agencies (e.g., Forest 

Service, Bureau of Land Management, or Bureau of Indian Affairs) or by non- federal entities 

(e.g., Grazing Association or County Pest District). APHIS may choose to assist these groups in 

a variety of ways, such as:

a) loaning equipment (an agreement may be required):

b) contributing in-kind services such as surveys to determine insect species, instars, and 

infestation levels;

c) monitoring for effectiveness of the treatment;

d) providing technical guidance.

9) In areas considered for treatment, State-registered beekeepers and organic producers shall be 

notified in advance of proposed treatments. If necessary, non-treated buffer zones can be

established.

Operational Procedures

GENERAL PROCEDURES FOR ALL AERIAL AND GROUND APPLICATIONS

1) Follow all applicable Federal, Tribal, State and local laws and regulations in conducting 

grasshopper and Mormon cricket suppression treatments.

2) Notify residents within treatment areas, or their designated representatives, prior to proposed 

operations. Advise them of the control method to be used, proposed method of application, and 

precautions to be taken.

3) One of the following insecticides that are labeled for rangeland use can be used for a 

suppression treatment of grasshoppers and Mormon crickets:

a) Carbaryl

i) solid bait

ii) ultra-low volume (ULV) spray

b) Diflubenzuron ULV spray

c) Malathion ULV spray
Appendix A

50

4) Do not apply insecticides directly to water bodies (defined herein as reservoirs, lakes, ponds, 

pools left by seasonal streams, springs, wetlands, and perennial streams and rivers).

Furthermore, provide the following buffers for water bodies:

• 500-foot buffer with aerial liquid insecticide.

• 200 foot buffer with ground liquid insecticide.

• 200-foot buffer with aerial bait.

• 50-foot buffer with ground bait.

5) Instruct program personnel in the safe use of equipment, materials and procedures; supervise to 

ensure safety procedures are properly followed.

6) Conduct mixing, loading, and unloading in an approved area where an accidental spill would 

not contaminate a water body.

7) Each aerial suppression program will have a Contracting Officer’s Representative (COR) OR a 

Treatment Manager on site. Each State will have at least one COR available to assist the 

Contracting Officer (CO) in GH/MC aerial suppression programs.

NOTE: A Treatment Manager is an individual that the COR has delegated authority to 

oversee the actual suppression treatment; someone who is on the treatment site and 

overseeing / coordinating the treatment and communicating with the COR. No specific 

training is required, but knowledge of the Aerial Application Manual and treatment 

experience is critical; attendance to the Aerial Applicators Workshop is very beneficial.

8) Each suppression program will conduct environmental monitoring as outlined in the current 

year’s Environmental Monitoring Plan.

APHIS will assess and monitor rangeland treatments for the efficacy of the treatment, to 

verify that a suppression treatment program has properly been implemented, and to assure 

that any environmentally sensitive sites are protected.

9) APHIS reporting requirements associated with grasshopper / Mormon cricket suppression 

treatments can be found in the APHIS Grasshopper Program Guidebook:

http://www.aphis.usda.gov/import_export/plants/manuals/domestic/downloads/grasshopper.pdf

SPECIFIC PROCEDURES FOR AERIAL APPLICATIONS

1) APHIS Aerial treatment contracts will adhere to the current year’s Statement of Work (SOW)

2) Minimize the potential for drift and volatilization by not using ULV sprays when the following 

conditions exist in the spray area:

a) Wind velocity exceeds 10 miles per hour (unless state law requires lower wind speed);

b) Rain is falling or is imminent;

c) Dew is present over large areas within the treatment block;

d) There is air turbulence that could affect the spray deposition;

e) Temperature inversions (ground temperature higher than air temperature) develop and 

deposition onto the ground is affected.
Appendix A

51

3) Weather conditions will be monitored and documented during application and 

treatment will be suspended when conditions could jeopardize the correct spray 

placement or pilotsafety.

4) Application aircraft will fly at a median altitude of 1 to 1.5 times the wingspan of 

the aircraft whenever possible or as specified by the COR or the Treatment

Manager.

5) Whenever possible, plan aerial ferrying and turnaround routes to avoid flights over

congested areas, water bodies, and other sensitive areas that are not to be treated.
52

Appendix B

2019 Grasshopper Survey Cumulative
Appendix B

53

2019 Mormon Cricket Survey Cumulative
54

Appendix C 

Table 1

United States Department of the Interior

FISH AND WILDLIFE SERVICE

Reno Fish And Wildlife Office 

1340 Financial Boulevard, Suite 234

Reno, NV 89502-7147

Phone: (775) 861-6300 Fax: (775) 861-630

http://www.fws.gov/nevada/

In Reply Refer To:

Consultation Code: 08ENVD00-2019-SLI-0165 

Event Code: 08ENVD00-2020-E-00485

Project Name: NV-04-20

Subject: Updated list of threatened and endangered species that may occur in your proposed 

project location, and/or may be affected by your proposed project

Official Species List

This list is provided pursuant to Section 7 of the Endangered Species Act, and fulfills the 

requirement for Federal agencies to "request of the Secretary of the Interior information whether 

any species which is listed or proposed to be listed may be present in the area of a proposed 

action".

This species list is provided by:

Reno Fish And Wildlife Office

1340 Financial Boulevard, Suite 234

Reno, NV 89502-7147

(775) 861-6300
Appendix C

Table 1

55

Project Summary

Consultation Code: 08ENVD00-2019-SLI-0165 

Event Code: 08ENVD00-2020-E-00485

Project Name: NV-04-20

Project Type: INVASIVE SPECIES CONTROL

Project Description: Site Specific Environmental Assessment for Rangeland Grasshopper and 

Mormon Cricket Suppression Program in Elko, Eureka, and Lander 

counties in Nevada.

Project Location:

Approximate location of the project can be viewed in Google Maps: 

https:// www.google.com/maps/place/40.54783433197417N115.66768532214437W

Counties: Elko, NV | Eureka, NV | Lander, NV
Appendix C

Table 1

56

Endangered Species Act Species 

There is a total of 6 threatened, endangered, or candidate species on this species list.

Species on this list should be considered in an effects analysis for your project and could 

include species that exist in another geographic area. For example, certain fish may appear on

the species list because a project could affect downstream species.

IPaC does not display listed species or critical habitats under the sole jurisdiction of NOAA 

Fisheries1, as USFWS does not have the authority to speak on behalf of NOAA and the 

Department of Commerce.

See the "Critical habitats" section below for those critical habitats that lie wholly or partially 

within your project area under this office's jurisdiction. Please contact the designated FWS 

office if you have questions.

1. NOAA Fisheries, also known as the National Marine Fisheries Service (NMFS), is an 

office of the National Oceanic and Atmospheric Administration within the Department 

of Commerce.

Mammals

NAME STATUS

Gray Wolf Canis lupus

Population: Western Distinct Population Segment

No critical habitat has been designated for this species.

Proposed 

Endangered

Fishes

NAME STATUS

Bull Trout Salvelinus confluentus

Population: U.S.A., conterminous, lower 48 states

There is final critical habitat for this species. Your location overlaps the critical habitat. 

Species profile: https://ecos.fws.gov/ecp/species/8212

Threatened

Clover Valley Speckled Dace Rhinichthys osculus oligoporus

No critical habitat has been designated for this species. 

Species profile: https://ecos.fws.gov/ecp/species/318

Endangered
Appendix C

Table 1

57

NAME STATUS

Independence Valley Speckled Dace Rhinichthys osculus lethoporus

No critical habitat has been designated for this species. 

Species profile: https://ecos.fws.gov/ecp/species/1982

Endangered

Lahontan Cutthroat Trout Oncorhynchus clarkii henshawi

No critical habitat has been designated for this species. 

Species profile: https://ecos.fws.gov/ecp/species/3964

Species survey guidelines:

https://ecos.fws.gov/ipac/guideline/survey/population/233/office/14320.pdf

Threatened

Conifers and Cycads

NAME STATUS

Whitebark Pine Pinus albicaulis

No critical habitat has been designated for this species. 

Species profile: https://ecos.fws.gov/ecp/species/1748

Candidate

Critical habitats

There is 1 critical habitat wholly or partially within your project area under this office's 

jurisdiction.

NAME STATUS

Bull Trout Salvelinus confluentus

https://ecos.fws.gov/ecp/species/8212#crithab

Final

 
Appendix C

Table 1

58

USFWS National Wildlife Refuge Lands AndFish Hatcheries

Any activity proposed on lands managed by the National Wildlife Refuge system must undergo a 

'Compatibility Determination' conducted by the Refuge. Please contact the individual Refuges to 

discuss any questions or concerns.

The following FWS National Wildlife Refuge Lands and Fish Hatcheries lie fully or partially 

within your project area:

FACILITY NAME ACRES

Ruby Lake National WildlifeRefuge 

Ruby Lake National Wildlife Refuge 

Hc 60 Box 860

Ruby Valley, NV 89833-9802

(775) 779-2237

https://www.fws.gov/refuges/profiles/index.cfm?id=84570

41,100

 

 
Appendix C

Table 1

59

Migratory Birds

Certain birds are protected under the Migratory Bird Treaty Act1 and the Bald and Golden Eagle 

Protection Act2.

Any person or organization who plans or conducts activities that may result in impacts to 

migratory birds, eagles, and their habitats should follow appropriate regulations and consider 

implementing appropriate conservation measures, as described below.

1. The Migratory Birds Treaty Act of 1918.

2. The Bald and Golden Eagle Protection Act of1940. 

3. 50 C.F.R. Sec. 10.12 and 16 U.S.C. Sec. 668(a)

The birds listed below are birds of particular concern either because they occur on the USFWS

Birds of Conservation Concern (BCC) list or warrant special attention in your project location. 

To learn more about the levels of concern for birds on your list and how this list is generated, see 

the FAQ below. This is not a list of every bird you may find in this location, nor a guarantee that 

every bird on this list will be found in your project area. To see exact locations of where birders 

and the general public have sighted birds in and around your project area, visit the E-bird data

mapping tool (Tip: enter your location, desired date range and a species on your list). For 

projects that occur off the Atlantic Coast, additional maps and models detailing the relative 

occurrence and abundance of bird species on your list are available. Links to additional 

information about Atlantic Coast birds, and other important information about your migratory 

bird list, including how to properly interpret and use your migratory bird report, can be found 

below.

For guidance on when to schedule activities or implement avoidance and minimization measures 

to reduce impacts to migratory birds on your list, click on the PROBABILITY OF PRESENCE 

SUMMARY at the top of your list to see when these birds are most likely to be present and 

breeding in your project area.

NAME

Bald Eagle Haliaeetus leucocephalus

This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention 

because of the Eagle Act or for potential susceptibilities in offshore areas from certain types 

of development or activities.

https://ecos.fws.gov/ecp/species/1626

BREEDING SEASON

Breeds Dec 1 to 

Aug 31

Black Rosy-finch Leucosticte atrata

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9460

Breeds Jun 15

to Aug 31
Appendix C

Table 1

60

NAME

Brewer's Sparrow Spizella breweri

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/9291

BREEDING SEASON

Breeds May 15

to Aug 10

Clark's Grebe Aechmophorus clarkii

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

Breeds Jan 1 to 

Dec 31

Golden Eagle Aquila chrysaetos

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/1680

Breeds Dec 1 to 

Aug 31

Green-tailed Towhee Pipilo chlorurus

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/9444

Breeds May 1

to Aug 10

Lesser Yellowlegs Tringa flavipes

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9679

Breeds 

elsewhere

Lewis's Woodpecker Melanerpes lewis

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9408

Breeds Apr 20

to Sep 30

Long-billed Curlew Numenius americanus

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/5511

Breeds Apr 1 to 

Jul 31

Marbled Godwit Limosa fedoa

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9481

Breeds 

elsewhere

Olive-sided Flycatcher Contopus cooperi

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/3914

Breeds May 20

to Aug 31

Pinyon Jay Gymnorhinus cyanocephalus

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9420

Breeds Feb 15

to Jul 15
Appendix C

Table 1

61

NAME

Sage Thrasher Oreoscoptes montanus

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/9433

BREEDING SEASON

Breeds Apr 15

to Aug 10

Virginia's Warbler Vermivora virginiae

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

https://ecos.fws.gov/ecp/species/9441

Breeds May 1

to Jul 31

Willet Tringa semipalmata

This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA 

and Alaska.

Breeds Apr 20

to Aug 5

Williamson's Sapsucker Sphyrapicus thyroideus

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/8832

Breeds May 1

to Jul 31

Willow Flycatcher Empidonax traillii

This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions 

(BCRs) in the continental USA

https://ecos.fws.gov/ecp/species/3482

Breeds May 20

to Aug 31
62

Appendix C 

Table 2

Part I

Grasshopper and Mormon Cricket Control Program 

Protection Measures Agreed to by APHIS to Protect 

Threatened, Endangered, or Proposed Species

Mammals

Common Name Scientific Name Listing Status States

A. Black-footed ferret Mustela nigripes E, EXPN CO, KS, MT, ND, NE, 

SD, UT, WY

Program personnel will consult with applicable Federal and/or State agencies in regard to the 

presence of black-footed ferrets prior to beginning any control programs. Each documented and 

verified occurrence of interest to the program will be considered and plans for adequate protection 

adopted in consultation with the local Fish and Wildlife Service (Service) field offices.

B. Utah prairie dog Cynomys parvidens T UT

Malathion and acephate will not be used within 1⁄4 mile of any Utah prairie dog town.

C. Hualapai Mexican vole Microtus mexicanus 

hualpaiensis

E AZ

One-quarter mile no malathion or acephate treatment buffer around occupied areas. Contact the 

local Service office prior to program operations in Mohave County.

D. Mexican long-nosed 

bat

Leptonycteris nivalis E NM, TX

Sanborn's long-nosed 

bat

Leptonycteris sanborni No Data No Data. AZ, NM ????

Lesser long-nosed bat Leptonycteris curasoae

yerbabuenae

E AZ, NM

No jeopardy foreseen because of low risk from pesticides to be used and prey base not expected to 

be significantly effected. Unquantifiable anticipated incidental take as a result of off-road vehicles 

use for surveys and application of carbaryl bait. Reasonable and prudent measures and terms and 

conditions provided to reduce take of the species.
Appendix C 

Table 2

63

Birds

Common Name Scientific Name Listing Status States

A. Whooping crane Grus americana E, EXPN CO, ID, KS, MT, ND,

NE, NM, OK, SD, 

TX, UT,WY

APHIS shall ensure that no whooping cranes have wandered into a proposed spray treatment or bait 

treatment area.

B. Bald eagle Haliaeetus

leucocephalus

T All 17 western States

Maintain a 1-mile radius treatment-free zone (including Nosema) around active bald eagle eyries 

found on rivers or lakes with no flyovers of this area by contract pilots.

A 2.5 mile no-aerial ULV spray zone will be maintained upstream and downstream from the nest 

site as a forage area. This will include a 0.25 mile buffer along each side of the rivers.

Lakes will be protected by a 0.25 no-aerial ULV spray buffer if they are considered foraging areas of 

the bald eagle.

C. Peregrine falcon Falco peregrinus anatum DM All 17 western States

This species has been delisted but is being monitored for the first 5 years.

D. Northern aplomado

falcon

Falco femoralis

septentrionalis

E TX

APHIS will contact the local Service office at least 5 days prior to grasshopper program activities to 

determine if nesting sites are known and coordinate necessary measures to protect nests and foraging 

areas.
Appendix C 

Table 2

64

E. Piping plover Charadrius melodus T CO, KS, MT, ND, NE, 

OK, SD, TX

No aerial ULV pesticides will be used within 0.25 mile of water bodies where piping plovers are 

known to nest.

Where carbaryl bran bait or Nosema is used, a 500-foot no-treatment zone around nesting areas of 

piping plovers should be maintained. Piping plover habitat will be determined in consultation with 

local Service field offices.

F. Western snowy plover Charadrius alexandrinus 

nivosus

T CA, WA, OR

No aerial ULV pesticides should be applied within 0.25 mile of the edges of known snowy plover 

nesting areas. Carbaryl bran bait or Nosema may be used to within 500 feet of these areas. Within 

the 500 foot buffer, no treatments will be made.

G. Interior least tern Sterna antillarum E CO, KS, MT, ND, NE, 

NM, OK, SD, TX

No aerial ULV application should be applied 2.5 miles up and down river to prevent abandonment 

of nesting least tern colonies due to aircraft flyovers and a possible decrease of the fishery forage 

base due to accidental aquatic applications.

A 0.25 mile no aerial ULV application buffer on each side of the river and around other bodies of 

water containing least tern colonies also should be observed.

A 500 foot no treatment zone around nesting colonies also should be observed.

Interior least tern habitat will be determined in consultation with the local Service field offices.

H. Yuma clapper rail Rallus longirostris

yumanensis

E AZ, CA

Maintain a 0.25 mile no aerial ULV application buffer and a 500 foot no application buffer for 

carbaryl bran bait and Nosema around nesting and foraging areas.
Appendix C 

Table 2

65

I. Black-capped vireo Vireo atricapillus E KS, OK, TX

Before APHIS control programs are initiated in Oklahoma, a concerted effort should be made to 

identify nesting areas of this species. The Service recommends that APHIS personnel contact our 

Service field office in Tulsa, which can assist in identifying specific nesting habitat. The 

Department of Biology, Central State University, Edmond, OK also can provide further assistancein 

this effort. Contact the Austin, TX field office for actions near black-capped vireo habitat in 

Callahan and Taylor Counties, TX.

Exclusion of aerial ULV spray application in habitat normally used for foraging and nesting 

by this species as identified above.

J. California brown pelican Pelecanus occidentalis 

californicus

E CA, OR, TX, WA

Maintain a 0.25 mile no aerial application buffer around established nests or roost sites. A 500 

foot buffer will apply for carbaryl bran bait or Nosema.

K. Southwestern willow

flycatcher

Empidonax traillii extimus E AZ, CA, CO, NM, TX, UT

No ULV application of insecticides should occur within 0.25 mile of the edge of occupied habitat. 

A buffer of 500 feet should be maintained where no application of carbaryl bran bait or Nosema is 

applied.

L. Mexican spotted owl Strix occidentalis lucida T AZ, CO, NM, TX, UT

APHIS will confer with the local Service office at least 5 days prior to grasshopper control activities 

in any of the counties known to contain Mexican spotted owls in northeastern Arizona, southwestern 

Colorado, and Utah to determine if protective measures are needed.

M. Cactus ferruginous 

pygmy-owl

Glaucidium brasilianum 

cactorum

E AZ

APHIS will confer with the local Service office at least 5 days prior to any grasshopper program 

activities to determine if protective measures are needed. APHIS adopt the preprogram conference 

procedures. If it is determined during site specific conferences that the grasshopper control program 

may jeopardize the continued existence of this species or result in the adverse modification of the 

species' proposed critical habitat, the Service will offer advisory recommendations to avoid or 

minimize any adverse effects.
Appendix C 

Table 2

66

Fish

Group A

Common Name Scientific Name Listing Status States

Bonytail chub Gila elegans E AZ, CA, CO, NV, UT

Colorado pikeminnow 

(=squawfish)

Ptychocheilus lucius E, EXPN E = AZ, CA, CO, UT, 

WY. EXPN = AZ

Cui-ui Chasmistes cujus E NV .

Gila trout Oncorhynchus gilae E AZ, NM

Greenback cutthroat trout Oncorhynchus stomias T CO

Humpback chub Gila cypha E AZ, CO, UT

Lahontan cutthroat trout Oncorhynchus clarkii

henshawi

T CA, NV, OR, UT

Pallid sturgeon Scaphirhynchus albus E KS, MT, ND, SD

Only carbaryl bran bait or Nosema (no aerial application of ULV pesticide) will be used within 0.25 

mile of occupied habitats.

Group B

Apache trout Oncorhynchus apache T AZ

Big Spring spinedace Lepidomeda mollispinis 

pratensis

T NV

Borax Lake-chub Gila boraxobius E OR

Chihuahua chub Gila nigrescens T NM

Desert dace Eremichthys acros T NV

Foskett speckled dace Rhinichthys osculus ssp. T OR

Gila topminnow (now

includes Yaqui)

Poeciliopsis occidentalis E AZ, NM

Hiko White River

springfish

Crenichthys baileyi

grandis

E NV

Hutton tui chub Gila bicolor spp. T OR

June sucker Chasmistes liorus E UT

Kendall Warm Springs

dace

Rhinichthys osculus

thermalis

T WY

Little Colorado spinedace Lepidomeda vittata T AZ

Modoc sucker Catostomus microps E CA

Pahrump killifish (poolfish) Empetrichthys latos E NV
Appendix C 

Table 2

67

Pahranagat roundtail chub Gila robusta jordani E NV

Pecos bluntnose shiner Notropis simus pecosensis T NM

Pecos gambusia Gambusia nobilis E NM, TX

Spikedace Meda fulgida T AZ, NM

Virgin River chub Gila robusta seminuda E AZ, NV, UT

Virgin spinedace

? Also listed under C?

Lepidomeda mollispinis

pratensis

T NV

Warner sucker Catostomus warnerensis T OR

White River springfish Crenichthys baileyi balleyi E NV

Woundfin Plagopterus 

argentissimus

E, EXPN E = AZ, NM, NV, UT 

EXPN = AZ, NM

No aerial ULV application of malathion should be applied within 1 mile of occupied habitat. A 0.25 

no-aerial ULV application of carbaryl and acephate also should be adhered to.

Group C

Arkansas River shiner Notropis girardi T KS, NM, OK, TX

Ash Meadows

Amargosa pupfish

Cyprinodon nevadensis

mionectes

E NV

Ash Meadows speckled

dace

Rhinichthys osculus

nevadensis

E NV

Clover Valley speckled

dace

Rhinichthys osculus

oligoporus

E NV

Delta smelt Hypomesus transpacificus T CA

Desert pupfish Cyprinodon macularius E AZ, CA

Devil's Hole pupfish Cyprinodon diabolis E NV

Independence Valley

speckled dace

Rhinichthys osculus

lethorporus

E NV

Leopard darter Percina pantherina . T OK

Loach minnow Tiaroga cobitis T AZ, NM

Lost River sucker Deltistes luxatus E CA, OR

Railroad Valley springfish Crenichthys nevadae T NV

Rio Grande silvery

minnow

Hybognathus amarus E NM, TX

Shortnose sucker Chasmiste brevirostris E CA, OR

Virgin spinedace

? Also listed under B?

lepidomeda mollispinis 

pratensis

T NV
Appendix C 

Table 2

68

Warm Springs pupfish Cyprinodon nevadensis 

pectoralis

E NV

White sturgeon Acipenser transmontanus E ID, MT

Yaqui topminnow

(Now included with Gila 

topminnow)

Poeciliopsis occidentalis 

sonoriensis

E AZ, NM

Buffers around areas of occurrence of 0.5 mile for the use of malathion and 0.25 mile for the use an 

aerially applied carbaryl and acephate. Within the buffers, only carbaryl bait or Nosema will be 

used.

Group D

Yaqui chub Gila purpurea E AZ

Neosho madtom Noturus placidus T KS, OK

Moapa dace Moapa coriacea E NV

No aerial ULV application of malathion should be applied within 0.5 mile of the habitat. A 0.25 

mile buffer should be applied for the use of acephate and carbaryl, and a 500 foot no-treatmentzone 

should be used for carbaryl bran bait.

Group E

Razorback sucker Xyrauchen texanus E AZ, CA, CO, NM, NV, 

UT, WY

Maintain a 0.25 mile no-aerial application buffer around known habitats. Within buffer, carbaryl 

bran bait or Nosema may be used within 500 feet of the water.

Group F

Sacramento splittail Pogonichthys T CA

No aerial applications of malathion within 0.5 mile, or aerial applications of acephate or carbaryl 

within 0.25 mile of Suisun Bay and the San Francisco Bay-Sacramento-San Joaquin River estuary in 

Sacramento and San Joaquin Counties. Within this buffer, carbaryl bran bait or Nosema may be 

used within 500 feet of the water.
Appendix C 

Table 2

69

Reptiles

Common Name Scientific Name Listing Status States

A. Desert tortoise Gopherus agassizii T, SAT AZ, CA, NV, UT

Malathion and acephate should not be applied in the Beaver Dam Slope of Washington 

County, Utah (both inside and outside of the designated critical habitat).

B. Flat-tailed horned lizard Phrynosoma mcallii No Data No Data

APHIS will maintain a 0.25 mile buffer for ULV aerial applications and a 500 foot buffer for 

carbaryl bran bait around known habitats.

C. New Mexican ridgenosed rattlesnakeCrotalus willardi obscurus T NM

If required to treat for grasshoppers above 6,000 foot elevation, local consultation with the Service 

will be conducted at least 5 days prior to grasshopper program activities to determine protection 

measures and specific areas that should be protected.

Amphibians

Common Name Scientific Name Listing Status States

A. Wyoming toad Bufo hemiophrys baxteri E WY

A 0.25 mile no-aerial ULV application buffer shall be maintained on each side of the Little Laramie 

River in Albany county, Wyoming.

To determine specific boundaries of the area, APHIS should contact the Helena, MT Endangered 

Species Field Office, as well as the Wyoming Game and Fish, prior to any control program within 

the historic range of the Wyoming toad.
Appendix C 

Table 2

70

B. Sonora tiger salamander Ambystoma tigrinum 

stebbinsi

E AZ

APHIS should not make aerial applications of malathion within 0.5 mile of occupied habitat of the 

salamander. Buffers of 0.25 mile for acephate and carbaryl aerial applications also should be 

maintained, and within the buffers only carbaryl bran bait or Nosema should be used.

C. California red-legged 

frog

Rana aurora draytonii T CA

No pesticides (acephate, carbaryl, carbaryl bran bait, or malathion) or Nosema should be applied 

within 1 mile of occupied habitat of the species.

Crustaceans

Common Name Scientific Name Listing Status States

Shasta crayfish Pacifastacus fortis E CA

Socorro isopod Thermosphaeroma

thermosphilus

E NM

Vernal pool fairy shrimp Branchinecta lynchi T CA, OR

No aerial ULV application of malathion or carbaryl should be applied within 1 mile ofthe 

habitat.

A 0.25 mile buffer should be applied for the use of acephate, and a 500 foot no-treatment zone 

should be used where carbaryl bran bait is used inside the no-spray buffer areas.
Appendix C 

Table 2

71

Snails

Common Name Scientific Name Listing Status States

A. Bruneau Hot Springs 

snail

Pyrgulopsis bruneauensis E ID

No pesticide should be broadcast aerially within 0.25 mile of Hot Creek in Owyhee County, Idaho. 

This is located at T. 8 S., R. 6 E, sections 2, 3, and 4; and T. 7 S., R. 6 E., sections, 33, 34, and 35.

B. Socorro springsnail Pyrgulopsis neomexicana E NM

Alamosa springsnail Tryonia alamosae E NM

No pesticide shou1d be applied aerially within 0.25 mile of the habitat. A 500 foot buffer would 

apply to carbaryl bran bait and Nosema.

C. Ouachita rock

pocketbook

Arkansia wheeleri E OK

No aerial application of malathion or carbaryl within 0.25 mile of habitat or within 500 feet of 

water for aerial application of acephate.

D. Banbury Springs 

limpet or lanx

Lanx sp. E ID

Bliss Rapids snail Taylorconcha serpenticola T ID

Idaho springsnail Fontelicella idahoensis E ID

Kanab ambersnail Oxyloma haydeni ssp. 

kanabensis

E AZ, UT

Snake River physa snail Physa natricina E ID

Utah valvata Valvata utahensis IE ID

Malathion should not be used within 0.5 mile of populations. A 0.25 mile buffer should be used for 

carbaryl and acephate, and a 500 foot buffer should be maintained for the use of carbaryl bran bait 

or Nosema.
Appendix C 

Table 2

72

Insects

Common Name Scientific Name Listing Status States

A. Pawnee montane 

skipper

Hesperia leonardus 

montana

T CO

No aerial application of pesticides within 0.25 mile of habitat.

B. American burying 

beetle

Nicrophorus americanus E NE, SD

Contact local office of the Service at least 5 days prior to program activities to determine specific 

habitat locations and develop adequate protection measures and treatment methods.

C. Ash Meadows naucorid Ambrysus amargosus T NV

No application within 0.25 mile of critical habitat.
Appendix C 

Table 2

73

Plants

Common Name Scientific Name Listing Status States

Group A

Arizona hedgehog cactus Echinocereus 

triglochidiatus var. 

arizonicus

E AZ

Aerial ULV application of pesticides will not be used within 0.25 of the occupied habitat.

Group B

Applegate's milk-vetch Astragalus applegatei E OR

Arizona agave Agave arizonica E AZ

Arizona cliffrose Purshia subintegra E AZ

Arizona willow Salix arizonica No Data No Data

Ash Meadows blazing-star Mentzelia leucophylla T NV

Ash Meadows gumplant Grindelia fraxinopratensis T CA, NV

Ash Meadows ivesia Ivesia kingii var. eremica T NV

Ash Meadows milk-vetch Astragalus phoenix T NV

Autumn buttercup Ranunculus acrifornis var. E UT

Barneby reed-mustard Schoenocrambe barnebyi E UT

Blowout penstemon Penstemon haydenii E NE, WY

Brady pincushion cactus Pediocactus bradyi E AZ

Clay-loving wild Eriogonum pelinophilum E CO

Clay phacelia Phacelia argillacea T UT

Clay reed-mustard Schoenocrambe argillacea T UT

Cochise pincushion cactus Coryphantha robbinsorum T AZ

Dudley Bluffs bladderpod Lesquerella congesta T CO
Appendix C 

Table 2

74

Dudley Bluffs twinpod Physaria obcordata T CO

Dwarf bear-poppy Arctomecon humilis E UT

Gypsum wild-buckwheat Eriogonum gypsophilum T NM

Heliotrope milk-vetch Astragalus montii T UT

Holy Ghost ipomopsis ipomopsis sancti-spiritus E NM

Jones cycladenia Cycladenia humilis var.

jonesii

T AZ, UT

Knowlton cactus Pediocactus knowltonii E CO, NM

Kodachrome bladderpod Lesquerella tumulosa E UT

Kuenzler hedgehog cactus Echinocereus fendleri var.

kuenzleri

E NM

Last Chance townsendia Townsendia aprica T UT

Lee pincushion cactus Coryphantha sneedii var.

leei

T NM

Lloyd's hedgehog cactus Echinocereus lloydii DR (Delisted) NM, TX

Maguire daisy Erigeron maguirei 

(var. maguirei)??

T UT

Malheur wire-lettuce Stephanomeria 

malheurensis

E OR

Mancos milk-vetch Astragalus humillimus E CO, NM

Mead's milkweed Asclepias meadii T KS

Mesa Verde cactus Sclerocactus mesa-verdae T CO, NM

North Park phacelia Phacelia formosula E CO

Oserhout milk-vetch Astragalus osterhoutii E CO

Parish's alkali grass Puccinellia parishii No Data No Data. CA, NM ?????

Peebles Navajo cactus Pediocactus peeblesianus 

var. peeblesianus

E AZ

Penland alpine fen mustard Eutrema penlandii T CO

Penland beardtongue Penstemon penlandii T CO

Rhizome (Zuni) fleabane Erigeron rhizomatus T NM

Sacramento Mountains

thistle

Cirsium vinaceum T NM

Sacramento prickly-poppy Argemone pleiacantha var. 

pinnatisecta

E NM
Appendix C 

Table 2

75

San Rafael cactus Pediocactus despainii E UT

Siler pincushion cactus Pediocactus 

(=Echinocactus = Utahia)

sileri

T AZ, UT

Slender orcutt grass Orcuttia tenuis T CA

Sneed pincushion cactus Coryphantha sneedii var.

sneedii

E NM, TX

Sodaville milk-vetch Astragalus lentiginosus

var. sesquimetralis

No Data No Data. NV ????

Spring-loving/centaury Centaurium namophilum T CA, NV

Steamboat buckwheat Eriogonum ovalifolium E NV

Toad-flax cress Glaucocarpum 

suffrutescens

No Data No Data. UT ????

Uinta basin hookless cactus Sclerocactus glaucus T CO, UT

Ute ladies'-tresses Spiranthes diluvialis T CO, ID, MT, NE, UT, 

WA, WY

Water howellia Howellia aquatilis T CA, ID, MT, OR, WA

Welsh's milkweed Asclepias welshii T AZ, UT

Western prairie fringed 

orchid

Platanthera praeclara T KS, ND, NE, OK

Winkler cactus Pediocactus winkleri T UT

Wright's fishhook cactus Sclerocactus wrightae E UT

Aerial application of pesticides will not be used within 3 miles of these species occupied habitats. 

Within the 3 mile buffer, only carbaryl bran bait or Nosema will be used.

Group C

Navajo sedge Carex specuicola T AZ, UT

No applications of carbaryl bran bait within 200 feet of springs and no aerial application of ULV 

pesticides within 500 feet of springs of occupied habitat.

Group D

Amargosa niterwort Nitrophila mohavensis E CA, NV

Ash Meadows sunray Enceliopsis nudicaulis var. 

corrugata

T NV

No applications of ULV insecticides will be made within 3 miles designated critical habitat. Within 

the 3 mile buffer, only carbaryl bran bait or Nosema will be used.
Appendix C 

Table 2

76

Group E

Canelo Hills ladies'-tresses Spiranthes delitescens E AZ

Huachuca water umbel Lilaeopsis schaffneriana E AZ

No applications of ULV insecticides will be made within 3 miles of known populations. Within the 

3 mile buffer, only carbaryl bran bait or Nosema will he used. Carbaryl bran bait will not be used 

within 20 yards of known populations of these species.
Appendix C 

Table 2

77

Part II

Species with "No Effect" or "No Jeopardy" 

Determinations Without Buffers or Other Measures

Mammals

Common Name Scientific Name Listing Status States

Gray wolf Canis lupus E CO, ID, MT, ND, SD, 

WA, WY

Grizzly bear Ursus arctos horribilis T CO, ID, MT, WA, WY

Mount Graham red squirrel Tamiasciurus hudsonicus 

grahamensis

E AZ

Woodland caribou Rangifer tarandus caribou E ID, WA

Birds

Aleutian Canada goose Branta canadensis 

leucopareia

DM

(Delisted)

CA, OR, WA

California condor Gymnogyps califonianus E, EXPN E = CA

EXPN = AZ, UT

Marbled murrelet Brachyramphus 

marmoratus marmoratus

T CA, OR, WA

Northern spotted owl Strix occidentalis caurina T CA, OR, WA

Red-cockaded woodpecker Picoides (=Dendrocopos) 

borealis

E OK, TX
Appendix C 

Table 2

78

Fish

Common Name Scientific Name Listing Status States

Beautiful shiner Cyprinella formosa T AZ, NM

Yaqui catfish Ictalurus pricei T AZ

Insects

Uncompahgre fritillary Boloria acrocnema E CO

Plants

MacFarlane's four-o'clock Mirabilis macfarlanei T ID, OR

Maguire primrose Primula maguirei T UT

Marsh sandwort Arenaria paludicola E CA, OR, WA

San Francisco Peaks

groundsel

Senecio franciscanus T AZ

Sentry milk-vetch Astragalus cremnophylax 

var. cremnophylax

E AZ

Todsen's pennyroyal Hedeoma todsenii E NM
79

Appendix C 

Table 3

Local Mitigation Measures Agreed to by USFWS 

and APHIS PPQ in 2004

Table 2. General Direct md Indirect Effects of Proposed Insecticides and Proposed Avoidance/mitigation Measures for Non-target Listed Animal and 

Plant Species

Non-Target Listed Species and 

Species Groups

Status Toxicity Levels Direct Effects Indirect 

Effects

Avoidance or 

Mitigation 

Measures

Counties2

Malathion Carbaryl Dimilin

BIRDS

Southwestern willow flycatcher E N/A3 N/A3 Low A,B,C 3,10 Clark, Lincoln, Nye

Bald Eagle T N/A3 N/A3 Low No Indirect 

Effects

5 Carson City, Churchill, Clark, 

Douglas, Elko, Esmeralda, 

Eureka, Humboldt, Lander, 

Lincoln, Lyon, Mineral, Nye, 

Pershing, Storey, Washoe, White 

Pine

Yuma clapper rail1 E Low Low Low A,B,C 7 Clark

REPTILE

Desert tortoise T,CH N/A3 N/A3 Slight A,B,C l Clark, Esmeralda, Lincoln, 

Nye

FISH

Warner sucker1 T, CH Moderate to

High

Moderate to

High

Slight A,B,C 2 Washoe

Cui-ui E N/A3 N/A3 Slight A.B,C,F 8 Storey, Washoe

White River springfish E, CH N/A3 N/A3 Slight A,B,C,F 8 Lincoln

Hiko White River springfish E, CH N/A3 N/A3 Slight A.B,C,F 8 Lincoln, Mineral

Railroad Valley springfish T, CH N/A3 N/A3 Slight A,B,C 8 Mineral, Nye

Devils Hole pupfish E N/A3 N/A3 Slight A,B,C 8 Clark, Nye

Ash Meadows Amargosa pupfish E, CH N/A3 N/A3 Slight A,B,C 8 Nye

Warm Springs pupfish E N/A3 N/A3 Slight A,B,C 8 Nye

Pahrump poolfish E N/A3 N/A3 Slight A,B,C 8 Clark, White Pine

Desert dace T, CH N/A3 N/A3 Slight A,B,C,F 8 Humboldt

Humpback chub E N/A3 N/A3 Slight A,B,C 8 Clark

Bonytail chub E, CH N/A3 N/A3 Slight A,B,C 8 Clark

Pahranagat roundtail chub E N/A3 N/A3 Slight A,B,C,F 8 Lincoln

Virgin River chub E, CH N/A3 N/A3 Slight A,B,C,F 8 Clark

White River spinedace1 E, CH Moderate to 

High

Very High Slight A,B,C 2 Nye, White Pine

Big Spring spinedace T, CH N/A3 N/A3 Slight A,B,C,F 8 Lincoln

Moapa dace E N/A3 N/A3 Slight A,B,C 8 Clark
Appendix C 

Table 3

80

Local Mitigation Measures Agreed to by USFWS 

and APHIS PPQ In 2004

Table 2. General Direct and Indirect Effects of Proposed Insecticides and Proposed Avoidance/mitigation Measures for Non-target Listed Animal and

Plant Species

Non-Target Listed Species and 

Species Groups

Status Toxicity Levels Direct Effects Indirect 

Effects

Avoidance or 

Mitigation 

Measures

Counties2

Malathion Carbaryl Dimilin

Lahontan cutthroat T N/A3 N/A3 Slight A,B,C 8 Carson City, Churchill, Clark, 

Douglas,Elko,Eureka, Humboldt,

Lander, Lyon, Mineral, Nye, 

Storey, Washoe

Woundfin E, CH N/A3 N/A3 Slight A,B,C,F 8 Clark

Colorado pikeminnow E N/A3 N/A3 Slight A,B,C 8 Clark

Independence Valley speckled

dace

E N/A3 N/A3 Slight A,B,C,F 8 Elko

Ash Meadows speckled dace E, CH N/A3 N/A3 Slight A,B,C 8 Nye

Clover Valley speckled dace E N/A3 N/A3 Slight A,B,C,E 8 Elko

Bull trout1 T Moderate to

High

Very High Slight A,B,C 2 Elko

Razorback sucker E, CH N/A3 N/A3 Slight A,B,C 8 Clark

INVERTEBRATES

Ash Meadows T, CH N/A3 N/A3 Very high 

larval stages

B,C 4 Nye

Carson wandering skipper1 E Very High Very High Very high

larval stages

B,C 2 Carson City, Washoe

PLANTS

Ash Meadows milkvetch T, CH N/A3 N/A3 Moderate to

Low

D,E 6 Nye

Spring-loving centaury T, CH N/A3 N/A3 Moderate to 

Low

D,E 6 Nye

Ash Meadows sunray T, CH N/A3 N/A3 Moderate to

Low

D,E 6 Nye

Steamboat buckwheat

E N/A3 N/A3 Moderate to

Low

D,E 6 Washoe

Ash Meadows gumplant T, CH N/A3 N/A3 Moderate to 

Low

D,E 6 Nye

Ash Meadows ivesia T, CH N/A3 N/A3 Moderate to 

Low

D,E 6 Nye

Ash Meadows blazing star T, CH N/A3 N/A3 Moderate to

Low

D,E 6 Nye

Amargosa niterwort E, CH N/A3 N/A3 Moderate to

Low

D,E 6 Nye

Ute lady's tresses1 T Very High Very High Moderate D,E 9 Lincoln
Appendix C 

Table 3 

81

Local Mitigation measures Agreed to by USFWS 

and APHIS PPQ in 2004

Table 2. General Direct and Indirect Effects of Proposed Insecticides and Proposed Avoidance/mitigation Measures for Non-target Listed Animal and 

Plant Species

Non-Target Listed Species and

Species Groups

Status Toxicity Levels Direct Effects Indirect

Effects

Avoidance or

Mitigation

Counties2

Malathion Carbaryl Dimilin

1

Other listed/proposed species that occur in Nevada, but were not previously addressed in the 1987 BO for USDA-APHIS-PPQ's 1987 Rangeland 

Grasshopper Cooperative Management Program or its amendments.

2

County(ies) where animal or plant species may be present. 3

N/A = Not Applicable; applies to insecticides that were covered under the 1987 National programmatic BO or its amendments.

E = Endangered; T = Threatened; PT = Proposed Threatened; CH = Critical Habitat

Indirect Effects

A. General loss of prey.

B. Limited Mobility of young to move out of treated area during nestingseason.

C. Ingestion of chemicals from vegetation and insects could affect survival or reproductive fitness.

D. Loss of important pollinators.

E. Loss of seed dispersal agents.

F. Exposure to chemicals from offsite transport via snow-melt or irrigation drainage.

Avoidance/Mitigation Measures

1. No aerial application of Dimilin®, malathion, or carbaryl within 1 mile of desert tortoise occupied habitat. In accordance with 1987 National 

programmatic BO for USDA-APHIS-PPQ's 1987 Rangeland Grasshopper Cooperative Management Program and its 1990 amendment, the 

USFWS's Southern Nevada Field Office will be given a 5 day notice prior to conducting aerial applications of insecticides in occupied desert

tortoise habitat.

2. No aerial application of Dimilin®, within 1 mile or malathion or carbaryl within 0.25 mile ofoccupied habitat.

3. A buffer of 500 feet should be maintained where no application of carbaryl bran bait is applied.

4. No aerial application of Dimilin® within 1 mile of occupied habitat.

5. Maintain a 1 mile radiustreatment-free zone around active bald eagle eyries found on rivers or lakes with no flyovers of this area by contact pilots. 

A 2.5 mile no-aerial spray zone will be maintained upstream and downstream from the nest site as a forage area. This will include a 0.25 mile 

buffer along each side of the rivers. Lakes will be protected by a 0.25 mile no aerial spray buffer if they are considered foraging areas of the bald

eagle.

6. Aerial application of Dimilin® will not be used within 3 miles of species occupied habitat.

7. No aerial application of Dimilin® within 1 mile or malathion or carbaryl within 0.25 mile of the edge of nesting and foraginghabitat.

8. No aerial application of Dimilin® within 1 mile of occupied habitat.

9. No aerial application of insecticides within 3 miles of the species occupied habitat. Within the 3 mile buffer only carbaryl bran bait will be used.

10. No aerial application of Dimilin® within 1 mile or malathion or carbaryl within 0.25 mile of the edges of occupied habitat.

PROPOSED MONITORING PLAN

Our environmental monitoring team has developed a draft environmental monitoring plan for the proposed 2020 rangeland grasshopper/cricket 

suppression program. USDA-APHIS-PPQ Directives 5640 .1 dated April 19, 2002, directs the agency to fulfill the mandates of NEPA, ESA, 

the Federal Insecticide, Fungicide and Rodenticide Act, and other statutes that require monitoring the effects of their actions on the 

environment.

Environmental monitoring is an integral component of the avoidance/mitigation measures outline in the PROPOSED 

AVOIDANCE/MITIAGAION MEASURES section. The primary goal of this environmental monitoring plan is to provide data which can 

be used to evaluate the effectiveness of the avoidance/mitigation measures proposed to protect the listed species outlined in the LISTED 

SPECIES section.

The monitoring methods proposed for the 2020 rangeland grasshopper/cricket suppression program include monitoring aerial applications 

of the liquid and bait forms of the insecticides used and for drift at selected sensitive sites primarily by collecting dye card, water and 

vegetation samples.

Amendment 1:

All mitigation measures agreed upon through local Sec 7 consultation shall apply, including but not limited to the 2018 Biological 

Assessment and subsequent concurrence.
82

Appendix D

APHIS response to public comments on the Nevada Draft EAs

(EA Number: NV-01-20; NV-02-20; NV-03-20; NV-04-20)

USDA APHIS received three public responses to the publication of the Draft EA. Public 

comments were received from the Xerces Society, the Center for Biological Diversity Center and 

an individual from the Bureau of Land Management.  Comments similar in nature were grouped 

under one response.  Comments that were editorial in nature or requested additional citations are 

not addressed in the appendix but were incorporated into the final EA, where appropriate.  The 

Grasshopper Program has decided not to use chlorantraniliprole in Nevada during 2020, therefore 

comments related to chlorantraniliprole were not addressed and all references to this 

chemical was removed from the final EA. 

Comment 1  

USDA APHIS received one comment about the EAs providing little in the way of solid 

information about where, how, and when the treatments may actually occur within the counties 

covered under the EAs, during the year 2020, which makes it impossible to determine if effects 

would actually be significant or not.  

APHIS described the purpose and need for grasshopper suppression treatments, potential 

treatment options, the affected environment within the state, and an analysis of the potential 

environmental consequences in the Draft EAs that were made available for public comment. 

These documents become programmatic because APHIS cannot precisely predict where an 

outbreak will occur each year; we only know that outbreaks will occur, and treatments in a 

timely manner will be absolutely necessary. The emergency response aspect is why site-specific 

treatment details cannot be known, analyzed, and published in advance. APHIS relies on its 

emergency provisions within its NEPA Implementing regulations (7 CFR 372.10) to address 

these situations.

Please be aware that local agreements with Tribal Nations may preclude disclosure of Tribal 

information to the public or outside of APHIS without the consent of the Tribal Administrator. 

Individuals may request information on the specific treatment areas on Tribal Lands from the 

individual Tribal Nations.

Comment 2  

USDA APHIS received one comment concerning the lack of transparency about the location of 

actual treatment areas, particularly on public lands, being a disservice to the public that prevents 

the public from reviewing sufficient information to be able to gauge justification for and the risks 

involved in the suppression effort.  

APHIS did not withhold the location of actual treatment areas while preparing the Draft EA, but 

rather those facts were not known at the time because economically damaging grasshopper 

populations had not become apparent. See previous comment concerning the prevention of the 

commenter’s ability to gauge the justification and risks of treatments within the proposed action 

areas.  
83

Comment 3

APHIS received one comment urging APHIS to provide the public with maps of specific 

treatment areas and proposed treatment strategies (including proposed date of application and 

chemical and rate to be used), immediately after approving any treatment and at least 14 days 

prior to implementation of any treatment. This comment suggested that this specific information 

be posted at the APHIS website as soon as it is available, sent to interested parties, and made 

available for public comment. 

In most circumstances, APHIS is not able to accurately predict specific treatment areas 

and treatment strategies months or even weeks before grasshopper populations reach economic 

infestation levels. The need for rapid and effective response when an outbreak occurs limits the 

options available to APHIS to inform the public other than those stakeholders who could be 

directly affected by the actual application. APHIS typically does not have 14 days between 

planning a treatment and the actual application because of the rapid population growth 

and potential damage of grasshopper infestations.  

Comment 4

APHIS received one comment that mentioned “APHIS’ procedure to approve or disapprove 

treatments based on a cost-benefit analysis performed using the “Hopper” model” and that is 

site-specific data are not available or current, APHIS must use protective values as defaults in 

Hopper.” 

The “Hopper” model is an older model and southwestern states (including NV) were never 

included in the model. 

In Nevada, general site specific data, which is used to determine treatments in real time and 

gathered at the time of actual surveys are used to make treatment decisions. The general site 

specific data include: grasshopper and/or Mormon cricket densities, species complex, dominant 

species, dominant life stage, terrain, soil types, range conditions, local weather patterns (wind, 

temp., precipitation), slope and aspect for hatching beds, grazing status and number of livestock 

grazing the site/allotment, and forage damage estimates. These are all factors taken into 

consideration during the survey season.   

Comment 5

APHIS received one comment concerning how analysis of projected economic injury levels and 

ultimately, treatment decisions, might be determined in the absence of site-specific data 

(specifically rangeland productivity and composition, precipitation and soil moisture, 

accessibility and cost of alternative forage, effectiveness of treatment, cost of treatment, timing 

of treatment, and grasshopper population density, life stage, and species composition).

See comment 4 above. In Nevada, general site specific data, which is used to determine 

treatments in real time and gathered at time of actual surveys are used to make treatment 

decisions.
84

Comment 6

APHIS received one comment related to disclosing its analysis for each of the seven variables 

mentioned in comment 5. 

The site specific data that is used to determine treatments in real-time is gathered at the time of 

actual surveys. This data is not available at the time that the environmental assessments are 

prepared. See comment 4 for an example of general site specific data used to determine 

treatments.

Comment 7

APHIS received one comment about providing the public with a more precise definition of when 

the threshold for spraying has been met. 

Economic thresholds are variable based on the value of protected resources and management 

objectives.  Baseline thresholds for Mormon crickets are 2 per sq. yd. and grasshoppers are 

8 per sq. yd., though neither of those thresholds guarantees justification for treatment alone. All 

of the site-specific data mentioned in comment 4 above are also considered for Nevada.

Comment 8

APHIS received one comment urging APHIS to delay release of the EAs and the publication of a 

FONSI until after treatment requests are received and all treatment areas have been delineated 

and are identified to the public. 

In Nevada, letters of request from were received in early April from the BLM districts for the 

2020 treatment season. Treatment areas are delineated during the survey process. The grazing 

allotments, which meet the treatment criteria, are identified to the requesting land managers.

Comment 9

APHIS received one comment regarding the EAs list four insecticide options (diflubenzuron, 

carbaryl, malathion, and chlorantraniliprole), and states that the choice of which to use will be 

site-specific, without being clear about how that choice of insecticide is made. 

In Nevada, diflubenzuron is the preferred insecticide for aerial treatments. Hot spot treatments 

are conducted using ground equipment primarily with carbaryl bait. The insecticides mentioned 

are options which could be used depending up the situation encountered at the time. The 

Grasshopper Program has decided not to use chlorantraniliprole in Nevada during 2020.

Letters of Request in previous years from land managers may be specific to use a particular 

insecticide and not treat during specific times of the day or on weekends.  These requests are 

adhered to by APHIS.

The letters of request come from individual land managers.  In the case of early instars, 

diflubenzuron, the preferred insecticide, can produce 90 to 97% mortality. If the window for the 

use of diflubenzuron closes, as a result of treatment delays, then the only other option would be 

the use of carbaryl 2% or 5% bait or malathion.  Malathion would only be used in an extreme 

situation where immediate control was required to avoid an economic crisis or an immediate 
85

threat to public safety. There are no plans to use malathion in Nevada in 2020. There are 

certain species which are susceptible to carbaryl bait. If the species complex present in the 

outbreak is not susceptible to bait and the diflubenzuron window is closed, then no treatments 

will occur. This is discussed with the requesting land managers.  

The final EA has been updated to reflect the changes in the program. 

Comment 10

APHIS received one comment concerning BeeREX calculating the expected environmental 

concentration (EEC) of diflubenzuron in pollen and nectar from foliar overspray as 1.76 mg/kg, 

which is equivalent to 1760 ppb. 

Nectar and pollen values in BeeREX are based on residues that would be expected to occur from 

direct pesticide applications to long grass which is a food source EPA estimates in its T-REX 

model.  These assumptions may overestimate expected residues of diflubenzuron in pollen and 

nectar.  Available data for diflubenzuron pollen residues in crops show a low frequency of 

occurrence and low concentrations.  The concentration in pollen will depend on application 

rates and when applications are made relative to flower bloom.  Program applications of 

diflubenzuron are at the lower end of labeled use rates for Dimilin due to the sensitivity of 

Orthoptera.  In addition, the Program uses rates less than the current labeled rates for 

grasshoppers and other labeled crops and makes only one application.

Comment 11

APHIS received one comment regarding chitin synthesis and its important in the early life stages 

of insects, as they molt and form a new exoskeleton in various growth stages. The specific 

concern was that aquatic guideline tests, (or terrestrial invertebrate acute tests), which typically 

run for 48 hours, may not capture a molting stage, and thus underrepresent acute toxicity. Single 

doses may cause mortality, if received at a vulnerable time, and consequently, conclusions from 

RQs based on acute toxicity studies for invertebrates may not fully represent actual risk. 

APHIS agrees that chitin synthesis is a critical function for terrestrial and aquatic invertebrates.  

APHIS in its risk assessments prepared for each Program insecticide summarized available 

acute and chronic toxicity data.  This would include studies of short duration such as 48 to 96 

hours as well as much longer term studies that would evaluate continuous exposures during 

critical life stages and development.

Comment 12

APHIS received the following comment, “For honey bees (the surrogate species for risk 

assessment in the absence of other data), USEPA (2018) reported a chronic 21-day ED50 and 

NOAEL of 0.012 and <0.0064 μg a.i./larva, respectively. Utilizing these values in BeeREX

(EPA’s model that calculates risk quotients for bees) and assuming an application rate of 

0.016 lb. a.i./ac, BeeREX calculates an acute dietary risk quotient of 18.13 and a chronic dietary 

risk quotient of 33.99. (A threshold value is 1.0). Risk quotients this high above 1.0 indicate a 

high concern for exposed bees. 
86

BeeREX is a tier one screening level model used by EPA to assess potential risk to pollinators. 

Estimates of risk quotients are used to determine if there is a presumption of risk that 

requires additional evaluation.  APHIS also relies on available field data to further characterize 

the risks of Program insecticides to terrestrial and aquatic invertebrates, where available. A 

limitation of BeeREX is it does not account for pesticide degradation that would normally occur 

in Program treatments.

Nectar and pollen values in BeeREX are based on residues that would be expected to occur from 

direct pesticide applications to long grass which is a food source EPA estimates in its T-REX 

model.  These assumptions may overestimate expected residues of diflubenzuron in pollen and 

nectar.  Available data for diflubenzuron pollen residues in crops with higher use rates show a 

low frequency of occurrence and low concentrations.  The concentration in pollen will depend on 

application rates and when applications are made relative to flower blooming.  Diflubenzuron 

Program applications are at the lower end of labeled use rates for Dimilin due to the sensitivity 

of Orthoptera.  In addition, the Program uses rates less than the current labeled rates and makes 

one application.

Comment 13

APHIS received one comment, regarding the EIS discloses that under some 

circumstances, Dimilin may be quite persistent; field dissipation studies in California citrus and 

Oregon apple orchards reported half-live values of 68.2 to 78 days. Rangeland persistence is 

unfortunately not available, but diflubenzuron applied to plants remains adsorbed to leaf surfaces 

for several weeks. 

Diflubenzuron persistence varies depending on site conditions.  Diflubenzuron degradation is 

microbially mediated with soil aerobic half-lives much less than dissipation half-lives.  While 

dissipation half-lives may extend up to 78 days, they have also been shown to be much less under 

other use patterns.

Comment 14

APHIS received the following comment, “APHIS discounted the pollinator risk by claiming that 

studies finding significant effects to pollinators utilized doses far above levels that would be used 

in grasshopper control. Unfortunately, this does not appear to be true for all studies 

cited.  Mommaerts et al. (2006) conducted dose-response assays and found that exposure to 

diflubenzuron resulted in reproductive effects in Bombus terrestris, with only the doses at 0.001 

of maximum field recommended concentrations (MFRC) in pollen and 0.0001 in sugar water 

resulting in effects statistically similar to controls. The MFRC for diflubenzuron is listed in the 

study as 288 mg/L (equivalent to 288,000 ppb). At 1/10,000 of this level, diflubenzuron effects 

would be similar to controls only at levels at or below 28.8 ppb while at 1/1000 of this level, 

diflubenzuron “no effect” concentrations would be equivalent to 288 ppb. This analysis thus 

shows the opposite of what APHIS claims – that the effective dose for reproductive effects is 

actually far below the EEC expected for diflubenzuron at RAATS rates used in grasshopper 

suppression. This raises concern that the application of diflubenzuron at the specified RAATS 

rates may cause severe impacts to bee reproduction within treated areas.” 
87

APHIS relied on available laboratory and field collected data for each Program insecticide to 

summarize risks to terrestrial invertebrates.  In evaluating studies, APHIS also evaluated likely 

routes of exposure for Program treatments.  Estimates of exposure using the EPA tier one 

screening model likely overestimate potential residues in pollen and nectar.   

Comment 15

APHIS received six comments about chlorantraniliprole. 

Chlorantraniliprole is not proposed for use in 2020. The final EA has been updated to reflect 

the changes in the program. 

Comment 16

APHIS received one comment concerning malathion being found to cause jeopardy in 1,284 

endangered species according to recent nationwide Biological Opinions 

APHIS recognize that EPA and the Services are continuing to develop updated national level 

consultations. APHIS currently consults with the Services at the State level for the Grasshopper 

program to ensure program activities do not adversely affect protected species or their critical 

habitat.

Comment 17

APHIS received one comment regarding the EPA determined that carbaryl is likely to adversely 

affect 1,542 species. 

The Endangered Species Act section 7 pesticide consultation process between the U.S. Fish and 

Wildlife Service and the National Marine Fisheries Service (the Services, collectively) and the 

EPA specifically concerns FIFRA pesticide registration and reregistration in the United States, 

including all registered uses of a pesticide. The state-level Biological Assessments for APHIS 

invasive species programs are separate from any consultations conducted in association with 

pesticide registration and reregistration process. The Agricultural Improvement Act of 2018 

(Farm Bill) created a partnership between USDA, EPA, the Services, and the Council on 

Environmental Quality to improve the consultation process for pesticide registration and 

reregistration. USDA is committed to working to ensure consultations are conducted in a timely, 

transparent manner and based on the best available science. The Revised Method for National 

Level Listed Species Biological Evaluations of Conventional Pesticides provides a directionally 

improved path to ensuring that pesticides can continue to be used safely for agricultural 

production with minimal impacts to threatened and endangered species. 

APHIS provided information about use of carbaryl to EPA for the FIFRA consultation for 

carbaryl.  The Grasshopper Program use of carbaryl has in the past comprised substantially less 

than 1% of the percent crop treated (PCT) for rangeland use of carbaryl. This is the case for the 

reasonably foreseeable future.  For rangeland, in the EPA BE, the Grasshopper Program’s very 

low usage was rounded up to <1% PCT, which gives an overestimate of rangeland acres treated 

and thus endangered species risk. APHIS use of carbaryl is even smaller compared to all uses of 

carbaryl nationwide. Further, the Grasshopper Program consults directly with the Services to 

ensure program activities do not adversely affect protected species or their critical habitat. 
88

Comment 18

APHIS received the following comment, “The jeopardy and LAA calls for malathion and 

carbaryl should be included in the EAs and should preclude the use of these chemicals.” 

APHIS consults directly with the U.S. Fish and Wildlife Service on treatments and methods. The 

U.S. Environmental Protection Agency’s consultation on pesticide registration across all 

nationwide uses of program pesticides does not provide sufficiently detailed analysis or 

conclusions relevant to the Grasshopper Program consultations to comply with the Endangered 

Species Act.

Comment 19

APHIS received one comment that it should take into account the risk to native bees and 

butterflies from these treatments, especially those designated species of greatest conservation 

need. APHIS should constrain its treatments to take into account pollinator conservation needs, 

and improve its monitoring capability to try to understand what non-target effects actually occur 

as a result of the different treatments. 

APHIS reduces the risk to native bees and pollinators through monitoring grasshopper and 

Mormon cricket populations and making pesticide applications in a manner that reduces the risk 

to this group of nontarget invertebrates.  Monitoring grasshopper and Mormon cricket 

populations allows APHIS to determine if populations require treatment and to make treatments 

in a timely manner reducing pesticide use and emphasizing the use of Program insecticides that 

are not broad spectrum.  Historical use of Program insecticides demonstrate that diflubenzuron 

is the preferred insecticide for use.  Over 90% of the acreage treated by the Program has been 

with diflubenzuron.  Diflubenzuron poses a reduced risk to native bees and pollinators compared 

to liquid carbaryl and malathion applications.  In addition APHIS used RAATs to treat 

approximately 99% of the acres historically treated by the Program.  APHIS also uses RAATs 

that are typically below the labeled RAAT rates further reducing the amount of insecticide used 

by the program.  APHIS also emphasizes the use of carbaryl bait, where applicable, as a means 

to suppress pest populations while protecting native bees and pollinators.  These methods 

of applications have been shown to be protective of nontarget invertebrates.  These studies are 

referenced and summarized in the EIS.

Comment 20

APHIS received the following comment, This EA and the EIS claim that the use of untreated 

swaths will mitigate impacts to natural enemies, bees, and other wildlife. However, the width of 

the skipped swaths is not designated in advance in the EA, and there is no minimum width 

specified.

APHIS assumes that the reduced amount of pesticide that would occur using untreated swaths 

over a given treatment block will result in reduced risk to nontarget organisms by reducing 

exposure. The swath width can vary based on site specific conditions, however, the end result is 

reduced pesticide exposure over a treatment area. The EIS cites studies that demonstrate that the 

use of RAATs result in higher nontarget invertebrate populations compared to treatment blocks 

that did not use RAATs.
89

Comment 21

APHIS received two comments/recommendations about minimum swath widths, “Without 

knowing minimum (rather than maximum) swath widths that will be applied under this EA, it is 

hard to compare results from this study (Lockwood et al. 2000) to the results on non-targets 

expected under RAATS in this EA. 2). APHIS should commit to science-based methodologies to 

assess actual risk from the proposed treatments and institute minimum untreated swath widths 

wide enough to meaningfully minimize exposure to bees and other beneficials.” 

Typically, APHIS employs 50% skip swaths when using RAATs. Swath widths and skips are 

determined by the type of plane doing the aerial application, the smallest being 75 feet, but the 

minimum skip swath is typically 100 feet because larger planes are often contracted.

The commenter references the work of Lockwood et al. 2000, this study 

looked at RAAT’s increasing swath widths by in some instances double skipping the untreated 

area. They also used ATV’s in their study which only have a minimum effect swath width of 30 

feet. Using modifications presently being done in Arizona, with the UTV’s ability to adjust 

hopper height, using the same ATV spreader, minimum effective swath width can be increased to 

40 feet. APHIS uses science based methodologies to assess treatment related benefits or 

risks. APHIS has for decades funded the Science and Technology Research Lab in Phoenix, 

Arizona, which is specific to Rangeland Grasshopper and Mormon Cricket Program research 

and development.  It is the only one of its kind in the U.S. The S&T Lab in cooperation with 

Arizona State University researchers have looked at nontarget studies in the past and have made 

recommendations to the Program side of APHIS. 

Comment 22

APHIS received the following comment, “Although the EIS included a quantitative analysis of 

drift anticipated from ULV aerial applications to estimate deposition into aquatic areas, an 

analysis is not presented or available to back up the assumption that untreated areas (skipped 

swath widths) will act as refugia for natural enemies, bees, and other wildlife.”

The EIS cites studies that demonstrate that the use of RAATs result in higher nontarget 

invertebrate populations compared to treatment blocks that did not use RAATs.

Comment 23

APHIS received three comments about the drift analysis described in the EA, 1) “The drift 

analysis described in the EA assumed a droplet spectra size of fine to very fine (median diameter 

= 137.5 μm). However, labels do not require a minimum droplet size for ULV applications over 

rangeland, and other uses of ULV technology for pest control assume much smaller droplet 

sizes.  EPA’s (2018) Ecological Risk Assessment for diflubenzuron uses AgDrift to estimate the 

drift fraction from aerial LV applications, although it is unclear whether AgDrift is validated for 

the purposes of predicting deposition of insecticides applied using ULV technology. EPA 

assumed a volume mean diameter (VMD) of 90 μm [note that this is approximately 2/3 of the 

VMD used in the APHIS analysis]. Under EPA’s analysis, the drift fraction comprises 19% at 

150 ft.”, 2) “APHIS should disclose its quantitative analysis and the percent drift it expects--by 

distance-- into untreated swaths for each application method it proposes”, and 3) “APHIS must 
90

also specify in its operational procedures the use of nozzles that will result in droplet spectra that 

accord with its analysis”. 

The VMD used by APHIS for diflubenzuron is the preferred median diameter used by the 

Program.  APHIS recognizes that the range of droplet sizes can vary under a ULV application.   

Comment 24

APHIS received a comment that it is “unrealistic that APHIS can comply with mitigation 

measures designed to protect bees on pesticide labels “(e.g., bumble bees fly earlier and later in 

the day, diflubenzuron is toxic to developing forms, if plants are flowering, bees are active, etc.).

APHIS utilizes diflubenzuron at far-lower levels than allowed by the label, thereby minimizing 

risks to non-targets, such as bees. There have been several studies on diflubenzuron effects on 

bees, such as Schroeder et al., 1980 and insect growth regulator effects reviewed in Tasei, 2001, 

which support the idea that the diflubenzuron levels APHIS uses for grasshoppers and Mormon 

crickets are a minimal risk to bees.  APHIS also complies with any label requirements designed 

to minimize impacts to pollinators.

Comment 25

APHIS received the following comment, “Except for untreated swath widths, the EA is silent on 

how it will avoid impact to pollinators. It has already been shown that within sprayed areas, risk 

quotients at expected application rates would be well above 1.0. Leaving skipped widths is also 

not a full solution at expected widths since, due to drift, untreated swaths are highly likely to be 

exposed to levels above risk quotients”. 

APHIS utilizes diflubenzuron at far-lower levels than allowed by the label, thereby minimizing 

risks to non-targets. Additionally, APHIS commonly incorporates untreated swaths into its 

treatment programs, which have consistently demonstrated reduced impacts on non-target 

arthropods (Lockwood et al., 1999, 2001; Norelius and Lockwood, 1999). 

Comment 26

APHIS received one comment regarding that APHIS must not ignore requirements listed on 

pesticide labels, nor make assumptions about its compliance with these when RAATS measures 

that will actually be taken are vague and unspecified. 

APHIS complies with all applicable Federal and State pesticide label language when making 

pesticide treatments.

Comment 27

APHIS received the following comment: “While flexibility with these may have been 

appropriate at the EIS stage, it is not appropriate at the EA stage. APHIS must fully disclose its 

RAATS plan for each treatment in the EA, including specifying application method, chemical to 

be used, rate, and width of untreated swaths.” 

RAATs are a dynamic treatment method based on size of the treatment area, species complex, 

and density of target species.  Specific details regarding RAATs cannot be determined until site 
91

specific data is collected during the 2020 survey season and an appropriate chemical is 

identified.  Once a treatment is determined necessary, application method, untreated swath 

widths, chemical choice, and application rate are included in the bid for contracting.

Comment 28

APHIS received one comment about to be consistent with the Pollinator-Friendly BMPs for 

Federal Lands (see Comment 7), APHIS must go beyond the general statements on the pesticide 

labels and specify more exactly how its spray plan will further reduce exposure and risk to bees. 

APHIS implements several BMP practices in their treatment strategies that are designed to 

protect nontarget invertebrates, including pollinators.  APHIS minimizes insecticide use by using 

lower than labeled rates for all Program insecticides, alternating swaths during 

treatment, making only one application per season and minimizing use of liquid broad spectrum 

insecticides.  APHIS also continues to evaluate new monitoring and control methods designed to 

increase the response to economically damaging populations of grasshoppers and Mormon 

crickets while protecting rangeland resources such as pollinators.

Comment 29

APHIS received one comment, “For listed and proposed species under the purview of the US 

Fish and Wildlife Service, the EAs lists "Species for Federal listing state-listed species, and/or 

other sensitive species identified by or federal agencies within the area." These lists are not 

consistent with the list included in a letter to APHIS from USFWS listing endangered, 

threatened, proposed, and candidate species inhabiting the project area (Appendix C, Table 1). 

To include just one example, in NV-01-20, the desert tortoise is not included as a listed species 

in the main body of the document even though Appendix C- Table 2 lists this species as 

specifically occurring within counties located in the project area.”

Appendix C, Table 1 will vary based on the area covered in the EA. The information in 

this table is pulled from iPAC, a USFWS resource that is used as planning tool to identify 

potential species that could occur in a given area.

USFWS provided a separate consultation listing the federally listed species covered by the 

northern Nevada office. Treatments in southern Nevada that overlapped with federally listed 

species would be addressed in a site specific consultation between both northern and southern 

Nevada USFWS offices. USFWS is aware that their consultation was supposed to include 

southern Nevada species but had not coordinated with the southern Nevada office. After 

communicating with USFWS, as long as we provide site specific maps, they can give us a site 

specific consultation to address any species that would be present in the treatment block and 

address any mitigation measures at that time. Future consultation will include both northern 

and southern USFWS offices.

Comment 30

APHIS received one comment, “In addition, the EA reports that “On June 25 2018, USFWS 

provided a letter of concurrence to APHIS personnel for the 2018, 2019, and 2020 treatment 

seasons.” However, the letter of concurrence is not included in the EA, and it is unclear if the 
92

letter of concurrence provided any mitigations for the use of chlorantraniliprole or if the letter of 

concurrence adopted the mitigations for listed species provided in Appendix C.”

These are documents used for interagency consultation between the Services and APHIS, as 

mandated by Section 7(a)(1) of the Endangered Species Act (ESA). There is no requirement 

under ESA or NEPA that requires consultation documents to be made available to the public for 

comment or review. The EA includes a section that discusses APHIS compliance with the ESA.

In Nevada, chlorantraniliprole is not proposed for use in 2020. The final EA has been 

updated to reflect the changes in the program.

Comment 31

APHIS received one comment, “Table 2 is described in the document as a list containing “the 

mitigations to be followed by APHIS when conducting a suppression program to control 

grasshoppers with insecticides other than diflubenzuron.” Yet chlorantraniliprole consultation is 

not complete, so Table 2 does not actually cover uses of chlorantraniliprole or the use of any 

chemical "other than diflubenzuron." APHIS needs to be more precise in the way it presents and 

characterizes the mitigations that are prescribed and for which species and which chemicals.”

Chlorantraniliprole is a viable chemical choice option for the APHIS grasshopper program, 

therefore it is included in the EA. Nevada will not be using chlorantraniliprole for the 2020 

treatment season. USFWS is aware of the new chemical addition and it will be included in 

future consultations.

Comment 32

APHIS received one comment, “In addition, because the measures are covered in two tables and 

because Tables 2 and 3 include species from outside the project area, the applicable mitigations 

that pertain to this EA are difficult to find and understand. It would be quite difficult for any 

applicator to integrate the requirements in these tables without specific directions and maps.

For decades APHIS in Nevada has consulted with and received concurrence from the state office 

of the USFWS. APHIS and USFWS develop and maintain mitigation measures for all listed and 

proposed T&E species within the state. These measures, which are listed in Tables 2 and 3 of 

each EA, are employed in every treatment project wherein said species occur. Tables 2 and 3 are 

included in the EA to outline nationally agreed upon mitigation measures as well as locally 

agreed upon mitigation measures.

Species protected by the ESA are identified through earlier consultation with the land manager 

and USFWS and those habitats would be buffered out using our agreed upon mitigation 

measures before the final map would be provided to the applicator.

Comment 33

APHIS received one comment “In addition, the general operational guidelines make no mention 

of the enhanced buffers required by NMFS, or the buffers or other specific requirements from 

USFWS imposed to protect listed, proposed, or candidate species.”
93

In Nevada, the general operational guidelines are provided in the EA’s to address protective 

measures for bodies of water without T&E species. The buffers for T&E species are addressed 

during the USFWS Section 7 consultations.

The ArcGIS map layers of T&E species and the buffers are taken into the field when delimiting 

treatment areas, this is completed to ensure that the buffered areas near the treatment areas 

correspond to the GIS data. The datasets are ground truthed in the field to ensure accuracy. 

When T&E species are associated with stock tanks these buffers are physically measured using 

survey grade measuring devices and or rangefinders. The buffered areas are then flagged for 

visibility as no entry areas for applicators. Enhanced buffers are included in tables 2 and 3 

of Appendix 3.

Comment 34

APHIS received one comment, “It appears that no consultation was completed for the use 

of chlorantraniliprole. APHIS must not utilize active ingredients for which consultation is 

incomplete.”

Chlorantraniliprole is not proposed for use in 2020. The final EA has been updated to reflect 

the changes in the program. 

Comment 35

APHIS received two comments concerning operationally, how will listed species’ protected 

locations be identified for ground and aerial applicators? How will such locations, buffer widths 

listed in the protective measures, and any specific instructions (i.e. use of carbaryl bait only) for 

some species be mapped and communicated to applicators? APHIS must provide to applicators 

a set of clear set of directions outlining protective measures for the listed and proposed species 

found within this project area and not burden applicators with a confusing set of directions split 

between multiple tables. 

  

Pilots are required to have GPS equipment capable of reading shapefiles which would include 

agreed upon buffers for any T&E species, critical habitat, or other sensitive sites. Pre-flight 

conversations prior to treatment would identify and make the applicator aware of any T&E 

species, sensitive sites, buffers, and species of conservation concern that warrant extra 

protection. 

See additional information in comments 32 and 33.

Comment 36

APHIS received one comment about pesticide specific conservation measures for each listed 

species, where appropriate, should be explicitly addressed and adopted. 

Agreed upon mitigation measures address specific chemicals when conservation measures are 

warranted.
94

Comment 37

APHIS received one comment that APHIS should adopt the following operational guideline 

across all site-specific EAs: “Use Global Positioning System (GPS) coordinates for pilot 

guidance on the parameters of the spray block. Ground flagging or markers should accompany 

GPS coordinates in delineating the project area as well as areas to omit from treatment (e.g., 

boundaries and buffers for bodies of water, habitats of protected species, etc.).” 

Specific pilot guidance capabilities are outlined in the contract and statement of work. Within 

the contract put out for bid to the applicators, GPS with data logging software requirements are 

the minimal standard for applicators to have prior to treatments. The pilot must be able to view 

shapefiles in the plane during the treatment to navigate the spray block. All sensitive sites are 

reviewed in the daily briefing with APHIS personnel who may be an applicator working on the 

treatment in a TDY capacity.

Comment 38

APHIS received one comment that, “APHIS states that it has no legal obligation to manage for 

vulnerable species not on the Endangered Species List. The essential role that pollinators play in 

the conservation of listed plant species is not addressed in the EAs and makes no mention of the 

fact that there are affirmative obligations incumbent on federal agencies with regard to protection 

of pollinators, regardless of whether they are federally listed including the 2014 Presidential 

Memorandum, the National Strategy to Promote the Health or Honey Bees and Other 

Pollinators, the Pollinator Friendly BMPs for Federal Land, and the Pollinator Research Action 

Item.” 

APHIS considers the role of pollinators in any consultations conducted with 

the USFWS to protect federally-listed plants.  Mitigation measures, such as no treatment buffers 

are applied with consideration of the protection of pollinators that are important to a particular 

listed plant species.

APHIS also implements several BMP practices in their treatment strategies that are designed to 

protect nontarget invertebrates, including pollinators.  APHIS minimizes insecticide use by using 

lower than labeled rates for all Program insecticides, alternating swaths during 

treatment, making only one application per season and minimizing use of liquid broad spectrum 

insecticides.  APHIS also continues to evaluate new monitoring and control methods designed to 

increase the response to economically damaging populations of grasshoppers and Mormon 

crickets while protecting rangeland resources such as pollinators.

Comment 39

APHIS received one comment, “The EAs disclose species listed as sensitive but does not list 

Species of Conservation Concern, or whether the state of Nevada designates any invertebrates as 

Species of Greatest Conservation Need.” 

Species of Conservation Concern are discussed during site-specific consultation between APHIS 

personnel, Nevada Department of Agriculture, Nevada Department of Wildlife, USFWS, and the 

land manager. Any species of conservation concern will have agreed upon mitigation measures 

in place before treatment will begin. 
95

Comment 40

APHIS received one comment regarding, the EAs, protections for at risk species, including the 

monarch butterfly which is currently being assessed for listing under the Endangered Species 

Act, are practically non-existent. 

Under USFWS Section 7 Act, there is no requirement to consult on sensitive species. However, 

in Nevada when there is concern by land management agencies, federal, state, etc.; APHIS has 

implemented protective measures for species of concern. Some examples included in the 2018-

2021 USFWS letter of concurrence are the Columbia spotted frog, Goose Creek milkvetch, and 

greater sage-grouse. This is a cooperative effort by APHIS between USFWS, Nevada 

Department of Wildlife, Nevada Department of Agriculture, or the requesting Land Management 

agency.

Comment 41

APHIS received one comment, “In the face of declining pollinator populations and the existence 

of federal directives for agencies to support and conserve pollinators and their habitat, APHIS 

must not conduct business as usual. APHIS should identify the at-risk pollinator species 

potentially present in the geographic area of the EAs and map their ranges prior to approving any 

treatment requests. Prior to treatment, APHIS should survey for presence of host plants and 

ensure that it has identified specific, actionable measures it will take to protect monarch habitat 

and the habitat of at-risk butterfly species from contamination that may occur as a result of 

exposure to treatment, such as designating a 125-ft buffer around identified habitat. Some ways 

to enact protections for at-risk species above and beyond those included in the EAs include: 

• Survey for butterfly host plants and avoid any applications to host plants. 

• Time pesticide applications to avoid exposure to at risk species. 

• Do not apply pesticides (especially insecticides) when monarchs (adult and immature) are 

present or expected to be present. 

• Avoid aerial applications. 

• Avoid using malathion and liquid carbaryl. 

• Include large buffers around all water sources, including intermittent and ephemeral 

streams, wetlands, and permanent streams and rivers, as well as threatened and 

endangered species habitat, honey bee hives, and any human-inhabited area. For 

example, Tepedino (2000) recommends a three-mile buffer around rare plant populations, 

as many of these are pollinated by solitary bees that are susceptible to grasshopper 

control chemicals.” 

APHIS includes many of the proposed measures to minimize risks to non-target organisms and 

human health.  These are summarized in the recent EIS.  For example no treatment buffers are 

applied to all water bodies and to areas where the public may potentially be exposed to Program 

applications.  APHIS also minimizes aerial insecticide use, where possible, however site 

conditions may dictate the need for aerial treatments.  APHIS minimizes use of liquid carbaryl 

and malathion which is reflected in the historical use for both insecticides. Diflubenzuron has 

been the preferred insecticide for making Program suppression treatments.  In addition APHIS 

has incorporated the use of RAATS in the Program as a means to reduce insecticide use 

providing reduced risk while meeting the goal of suppression.  APHIS continues to research and 

develop new techniques for management of grasshopper and Mormon cricket populations.
96

Comment 42

APHIS received the following comment, “While the mitigations that are identified for aquatic 

habitats in the EAs are heartening, APHIS should include monitoring for the presence and health 

of mussels in streams that traverse or are adjacent to treatment areas as part of its monitoring 

strategy.” 

APHIS agrees that freshwater mussels should be protected, as well as other aquatic organisms, 

and uses ground and aerial application no treatment buffers adjacent to all aquatic habitats. In 

addition APHIS uses reduced rates of Program insecticides compared to current labeled rates. 

These mitigation measures are beyond label requirements for protection of aquatic habitats. The 

intent of these buffers is to reduce off-site drift and runoff of Program insecticides to aquatic 

habitats.

APHIS conducts environmental monitoring related to Program treatments.  Monitoring is 

typically done adjacent to any sensitive habitats, including aquatic habitats, to determine 

pesticide residues. These data can be used to determine risk to non-target organisms based on 

available toxicity data.

Comment 43

APHIS received three comments about stock tanks, 1. “The EAs do not discuss water bodies of 

anthropogenic origin, such as stock tanks or stock ponds, “APHIS should recognize the potential 

for stock pond/tanks to contribute significantly to the diversity of aquatic invertebrates in 

rangelands”, and 3. APHIS should identify and map all stock tanks/ponds and specify a buffer 

around stock ponds/tanks from chemical treatment at least equivalent to that specified for 

wetlands, in order to protect aquatic diversity.”

All bodies of water are buffered according to the APHIS Guidelines in Appendix 1 of Draft EA.

Stock tanks, stock ponds, and other anthropogenic sources of water are buffered in the same 

manner as any other natural source of water in or around the treatment area. All anthropogenic 

sources of water, if they cannot be drained, covered, or removed will be buffered in concurrence 

with our standard water buffer mitigations. Any sensitive species or species of conservation 

concern would be addressed with the land manager and mitigation measures agreed upon prior 

to treatment.

In Nevada, APHIS personnel work with the land managing agency to identify locations of any 

sensitive sites including stock tanks/ponds. During delimiting survey, any unidentified stock 

tanks, stock ponds, or other bodies of water, natural and anthropogenic, are marked with their 

GPS coordinates and buffers created to avoid treatment of the sensitive sites.

Comment 44

APHIS received one comment, “APHIS’ reactive strategy includes no mention of what is most 

sorely needed: cooperation and planning with land managers to take appropriate steps to prevent 

the types of grasshopper and cricket outbreaks that are now dealt with by chemical controls.”

APHIS is not a land management agency, but encourages IPM through past and current 

research and will continue to do so.
97

APHIS supports the use of IPM in the management of grasshoppers and Mormon Crickets. 

APHIS provides technical assistance to Federal, Tribal, State and private land managers 

including the use of IPM. However, implementation of on-the-ground IPM activities is limited to 

land management agencies and Tribes, as well as private land owners. In addition, APHIS’ 

authority under the Plant Protection Act is to treat Federal, State and private lands for 

grasshoppers and Mormon cricket populations. APHIS’ technical assistance occurs under each 

of the three alternatives proposed in the EIS.

In addition to providing technical assistance, APHIS completed the Grasshopper Integrated Pest 

Management (GIPM) project, which is discussed in more detail on page 21 of the EIS. One of 

the goals of the GIPM is to develop new methods of suppressing grasshopper and Mormon 

cricket populations that will reduce non-target effects. RAATs are one of the methods that has 

been developed to reduce the amount of pesticide used in suppression activities, and is a 

component of IPM. APHIS continues to evaluate new suppression tools and methods for 

grasshopper and Mormon cricket populations, including biological control, and as stated in the 

EIS, will implement those methods once proven effective and approved for use in the United 

States.

Comment 45

APHIS received one comment: “Emphasizing cultural techniques through appropriate grazing 

management could help to minimize pesticide application and allow natural enemies to regulate 

grasshopper and Mormon cricket populations to the greatest extent possible. While more 

research is needed to develop species- and region-specific management treatments that use 

alternatives to pesticides (Vermeire et al. 2004), there is likely enough data to employ cultural 

techniques now.”

APHIS supports the use of IPM in the management of grasshoppers and Mormon Crickets. 

APHIS provides technical assistance to Federal, Tribal, State and private land managers 

including the use of IPM, including cultural techniques. However, implementation of on-theground IPM activities is limited to land management agencies and Tribes, as well as private land 

owners. In addition, APHIS’ authority under the Plant Protection Act is to treat Federal, State 

and private lands for grasshoppers and Mormon cricket populations.

Comment 46

APHIS received one comment that, “APHIS must elevate the expectation of preventative 

approaches in its cooperative agreements with other land management agencies. APHIS can 

collaborate with agencies (such as the Natural Resource Conservation Service (NRCS), the Farm 

Service Agency (FSA), and State Extension program) to facilitate discussion and disseminate 

information to ranchers about preventative measures that can be taken and alternatives to 

pesticide use.”

APHIS supports the use of IPM in the management of grasshoppers and Mormon Crickets. 

APHIS provides technical assistance to Federal, Tribal, State and private land managers 

including the use of IPM, including cultural techniques. However, implementation of on-theground IPM activities is limited to land management agencies and Tribes, as well as private 
98

land owners. In addition, APHIS’ authority under the Plant Protection Act is to treat Federal, 

State and private lands for grasshoppers and Mormon cricket populations.

APHIS has maintained cooperative relationships with state and federal land managers as well as 

private landowners and Indian tribes for decades. Those relationships have allowed APHIS to 

provide consistent and continual recommendations on land management practices which might 

help mitigate orthopteran infestations.

In Nevada, public meetings were held throughout the week of February 24th in the towns of 

Winnemucca, Battle Mountain, Elko, Ely, Austin, and Reno. One objective of holding 

public meetings is to disseminate information to ranchers, private landowners, state extension 

programs, and other government agencies. This allows the public to reach out to their local 

extension offices to find out more about managing Mormon crickets and grasshoppers or 

contacting the agency.

Comment 47

APHIS received on comment that, “APHIS and/or collaborating agencies should investigate and 

implement opportunities to incentivize healthy range management practices.”

As part of its ongoing IPM strategy to manage grasshoppers and Mormon cricket outbreaks, 

APHIS collaborates with scientists and land managers focused on rangeland health.

Comment 48

APHIS received one comment that, “APHIS and its partners should be approaching the problem 

by keeping a focus on the potential to reduce grasshopper carrying capacity by making the 

rangeland environment less hospitable for the pests. APHIS must not take a limited view of its 

role and responsibilities, and should utilize any available mechanism to require land management 

agencies to diminish the severity, frequency and duration of grasshopper outbreaks by utilizing 

cultural management actions. Memoranda of Understanding (MOUs) should be examined and 

updated to ensure that land management agencies are accountable in utilizing cultural techniques 

to diminish the carrying capacity of pest species.

APHIS supports the use of IPM in the management of grasshoppers and Mormon Crickets. 

APHIS provides technical assistance to Federal, Tribal, State and private land managers 

including the use of IPM. However, implementation of on-the-ground IPM activities is limited to 

land management agencies and Tribes, as well as private land owners. In addition, APHIS’ 

authority under the Plant Protection Act is to treat Federal, State and private lands for 

grasshoppers and Mormon cricket populations.

Comment 49

APHIS received a comment, “Longer-term strategic thinking should include:

• Prevent conditions that allow pest populations to survive and reproduce.

• Employ diverse management techniques (e.g., biological, physical, and cultural).

• Select pesticides to minimize risks to nontarget organisms.

• Implement frequent and intense monitoring to identify populations that can be controlled 

with small ground-based pesticide application equipment.
99

• Monitor sites before and after application of any insecticide to determine the efficacy of 

the pest management technique as well as if there is an impact on water quality or non-target 

species.”

APHIS currently monitors for grasshopper and Mormon cricket populations. These measures 

are employed to allow APHIS to respond with treatment, where warranted, treating the smallest 

area possible and if practical using ground-based equipment. APHIS, due to its monitoring 

efforts, has been able to rely on diflubenzuron as the primary insecticide used in the Program.

Diflubenzuron is a more selective insecticide compared to liquid carbaryl and malathion posing 

less risk to nontarget organisms. APHIS also uses environmental monitoring to assess 

application success and to determine if Program insecticides are reaching sensitive habitats, 

including aquatic habitats. APHIS supports the use of IPM in the management of grasshoppers 

and Mormon Crickets. APHIS provides technical assistance to Federal, Tribal, State and private 

land managers including the use of IPM. However, implementation of on-the-ground IPM 

activities is limited to land management agencies and Tribes, as well as private land owners. In 

addition, APHIS’ authority under the Plant Protection Act is to treat Federal, State and private 

lands for grasshoppers and Mormon cricket populations. APHIS continues to research and 

develop new methods for assessing and controlling grasshopper and Mormon cricket 

populations that can be incorporated into IPM practices. 

Comment 50

APHIS received one comment that, “The EAs do not make mention of any specific protections to 

be accorded to special status lands such as Wilderness areas, Wilderness study areas, Research 

Natural Areas, National Wildlife Refuges, and designated or proposed Areas of Critical 

Environmental Concern. These special status areas have been designated for specific purposes 

and generally discourage human intervention with the natural ecosystem. Grasshopper 

suppression should not be undertaken in such areas.”

APHIS does not make treatments on lands of special status without a request from that agency 

and an evaluation of whether treatments are necessary. Additional protection measures for 

these types of lands are established by the agency requesting treatment and are followed by 

APHIS.

Comment 51

APHIS received the following comment regarding, “We appreciate that public notice of this sitespecific EA and its comment period was posted at the APHIS website. It does not appear to have 

been the practice to post the Draft EAs in the last several years, but limiting public notice is 

contrary to the spirit of the NEPA process. Grasshopper suppression efforts are of more than 

local concern and as federal actions, should be noticed properly, i.e. beyond local stakeholder 

audiences, local newspapers, etc. We recommend that, in the future, notice of open public 

comment periods for all site-specific EAs for grasshopper suppression be posted in the Federal 

Register, and documents made available for review at regulations.gov and at the APHIS 

grasshopper website.”

Public involvement under the CEQ Regulations for Implementing the Procedural Provisions of 

NEPA distinguishes federal actions with effects of national concern from those with 
100

effects primarily of local concern (40 CFR 1506.6). Our EIS process for the GMC program was 

published in the Federal Register (APHIS-2016-0045), and met all applicable notice and 

comment requirements for a federal action with effects of national concern. This process 

provided individuals and national groups the ability to participate in the development of 

alternatives and provide comment. Our subsequent state-based actions have the potential for 

effects of local concern, and we publish them according to the provisions that apply to federal 

actions with effects primarily of local concern. This includes the USDA APHIS NEPA 

Implementation Procedures, which allows for EAs and FONSIs where the effects of an action are 

primarily of regional or local concern to normally provide publication in a local or area 

newspaper of general circulation (7 CFR 372.7(b)(3)). These publications provide potentially 

locally-affected individuals an additional opportunity to provide input into the decision-making 

process. Some states also provide additional opportunities for local public involvement, such as 

public meetings.

Comment 52

APHIS received the following comments, “The Draft Environmental Assessments Frustrate 

Public Participation.” “APHIS frustrated public participation by failing to inform interested 

parties of the existence of the EAs.”

“Scoping” is the process APHIS uses through which the agency and the public identify 

alternatives and issues to be considered during the development of a grasshopper or Mormon 

cricket suppression program. Scoping was helpful in the preparation of the draft Environmental 

Assessments (EAs). The process can occur formally and informally through meetings, 

conversations, or written comments from individuals and groups.

Prior to the treatment season, APHIS conducted meetings or provided guidance for public 

participation in the decision making process. In addition, APHIS notified Federal, State and 

Tribal land managers and private landowners of the potential for grasshopper and Mormon 

cricket outbreaks on their lands.

In Nevada, prior to the treatment season, letters of request from land managers were 

received from land managers. Letters for the 2020 treatment season were received in early April. 

Public meetings were held across the state between February 24th and February 27th to 

discuss the Draft EA and local concerns. Notice of public comment was published in local 

newspapers and distributed to various state and county stakeholders for distribution to other 

interested parties. The comment period opened March 6th, 2020 and expired April 7th, 2020. A 

report of grasshopper survey season and if any treatments conducted annual report is provided 

to land managers and/or stakeholders on annual basis.

Public meetings in Nevada were held in Winnemucca, with about 80 members of the public 

in attendance, Battle Mountain, with a handful of state/county extension cooperators, Elko, with 

approximately 10 members of the public and cooperating agency members, Eureka, with 1 

state/county cooperator, Austin, with approximately 3 people in attendance from county and 

state cooperators, and Reno, where we had 0 attendance.
101

Comment 53

APHIS received the following comment, “APHIS did not providing information for the 

submission of public comments including where and when to submit comments by.”

APHIS works to inform all interested parties about draft EA’s for comment. When an interested 

party asks to be informed, APHIS ensures contact information is added to the list of 

interested stakeholders. Each local office works to inform interested parties of the availability of 

an EA for comment. Any omission of an interested party is not intentional.

A notice of public comment was sent to all parties who expressed interest in the past or at public 

meetings in addition to the local newspapers, Tribal nations, and state, county, and extension 

cooperators. A letter of notice clearly defining the 30 day comment period and the contact 

information of local APHIS personnel responsible for drafting the state EAs was also sent out to 

the respective parties. 

Comment 54

APHIS received the following comments, “APHIS limited public notice to local papers.” “This 

local notice is insufficient as it excludes countless other interested parties.”

Public involvement under the CEQ Regulations for Implementing the Procedural Provisions of 

NEPA distinguishes federal actions with effects of national concern from those with effects 

primarily of local concern (40 CFR 1506.6). Our EIS process for the GMC program was 

published in the Federal Register (APHIS-2016-0045), and met all applicable notice and 

comment requirements for a federal action with effects of national concern. This process 

provided individuals and national groups the ability to participate in the development of 

alternatives and provide comment. Our subsequent state-based actions have the potential for 

effects of local concern, and we publish them according to the provisions that apply to federal 

actions with effects primarily of local concern. This includes the USDA APHIS NEPA 

Implementation Procedures, which allows for EAs and FONSIs where the effects of an action are 

primarily of regional or local concern to normally provide publication in a local or area 

newspaper of general circulation (7 CFR 372.7(b)(3)). These publications provide potentially 

locally-affected individuals an additional opportunity to provide input into the decision-making 

process. Some states also provide additional opportunities for local public involvement, such 

as public meetings.

A notice of public comment was sent to all parties who expressed interest in the past or at public 

meetings in addition to the local newspapers, tribal nations, and state, county, and extension 

cooperators. A letter of notice clearly defining the 30 day comment period and the contact 

information of local APHIS personnel responsible for drafting the state EAs was also sent out to 

the respective parties. In Nevada, public meetings were held on February 24th, 25th, 26th, and 

27th, 2020.

Comment 55

APHIS received the following comments, “APHIS provided a short public comment period 

during this COVID-19 pandemic.” “The 30 day comment deadline for the Draft EAs is wholly 

inappropriate during the current COVID-19 pandemic, where both staff and members of the 
102

concerned public have limited capacity, given the challenges associated with a global pandemic 

including but not limited to increased childcare demands, illness, etc.”

The comment period was in accordance with CEQ regulations, 40 C.F.R. § 1501.4(e)(2), In 

determining whether to prepare an environmental impact statement the Federal agency shall: (e) 

Prepare a finding of no significant impact, if the agency determines on the basis of the 

environmental assessment not to prepare a statement. (2) In certain limited circumstances, 

which the agency may cover in its procedures under § 1507.3, the agency shall make the finding 

of no significant impact available for public review (including State and area-wide 

clearinghouses) for 30 days before the agency makes its final determination whether to prepare 

an environmental impact statement and before the action may begin. CEQ guidance also notes: 

When preparing an EA, the agency has discretion as to the level of public involvement. The CEQ 

regulations state that the agency shall involve environmental agencies, applicants, and the 

public, to the extent practicable, in preparing EAs. Sometimes agencies will choose to mirror the 

scoping and public comment periods that are found in the EIS process. In other situations, 

agencies make the EA and a draft FONSI available to interested members of the public. APHIS 

would have considered extending the comment period if there had been a reason to believe that 

additional substantive issues remained, or that the pandemic itself created new issues.

In Nevada, public meetings were held on February 24th, 25th, 26th, and 27th, 2020. The World 

Health Organization did not declare COVID-19 a Pandemic until March 11, 2020. The CDC 

provided guidance for meetings of more than 50 people on March 15, 2020. Public interaction in 

Nevada was well before the National Concern and Governor Sisolak issuing a Stay at Home 

order on April 1, 2020. Comment period opened March 6th, 2020 and expired April 7th, 2020.

Comment 56

APHIS received the following comment, “the proposal in question is controversial and deals 

with issues of significant public interest.”

The USDA became involved in grasshopper control on Federal rangeland in the 1930s. During 

that decade, grasshopper infestations covered millions of acres in 17 Western States. 

Unsuccessful efforts to control grasshopper outbreaks on a local basis proved that grasshoppers 

needed to be dealt with on a broader basis. In 1934, Congress charged USDA with controlling 

grasshopper infestations on Federal rangeland. Thereafter, USDA was the lead agency in 

cooperative efforts among Federal agencies, State agriculture agencies, and private ranchers to 

control grasshopper outbreaks.

APHIS is not aware of any controversy in the program. Every year APHIS works with local 

stakeholders to gather information and discuss the grasshopper program. The grasshopper 

program requires a written request to treat on any land and discussions with the land owner or 

manager determine the course of the final action. APHIS acts in partnership with stakeholders 

through agreements and Memorandum of Understanding on all activities in the program. APHIS 

offers to exclude persons who do not wish for their land to be treated to opt out and be buffered 

from the treatment area. In general there has been support for APHIS to manage grasshopper 

and Mormon cricket populations in Nevada. 
103

Comment 57

APHIS received the following comment, “The Draft EAs also limit public participation by 

failing to provide contact information for the submission of written or electronic comments.”

The local offices emailed public notices to a list of stakeholders that they have collected over the 

years and also announced the open comment period in the local media. Those notices have the 

link for the EA’s for comment and the point of contact. In an attempt to be more transparent 

APHIS has placed Program EA’s on to the website for people to access. When an interested 

party asks to be informed, APHIS ensures their contact information is added to the list of 

interested stakeholders. Each local office works to inform interested parties of the availability of 

an EA for comment. Any omission of an interested party is not intentional. 

In Nevada, APHIS personnel identified any parties who expressed interest and delivered copies 

of the EA along with a notice for public comment. The EA and its notice of comment was 

delivered to local newspapers, Tribal nations, parties who expressed interest and state, county, 

and extension cooperators with a clearly defined 30 day comment period. Contact information 

of local APHIS personnel responsible for drafting the state EAs was included in the notice. 

Comment 58

APHIS received the following comment, “Nowhere on the webpage for the Draft Environmental 

Assessment Rangeland Grasshopper and Mormon Cricket Suppression Program is there any 

information on where to submit comments.”

The local offices emailed public notices to a list of stakeholders that they have collected over the 

years and they also announced the open comment period in the local media. Those notices have 

the link for the EA’s for comment and the point of contact. In an attempt to be more 

transparent, APHIS has placed Program EA’s on to the website for people to access. When an 

interested party asks to be informed, APHIS ensures their contact information is added to the list 

of interested stakeholders. Each local office works to inform interested parties of the availability 

of an EA for comment. Any omission of an interested party is not intentional. For Nevada (See 

Previous Response).

Comment 59

APHIS received the following comment, “Staff for USDA-APHIS that have been involved with 

the environmental review for this program were unable to readily provide information for the 

submission of public comment.”

The local offices emailed public notices to a list of stakeholders that they have collected over the 

years and they also announce the open comment period in the local media. Those notices have 

the link for the EA’s for comment and the point of contact. In an attempt to be more transparent, 

we have put all of our EA’s on to the website for people to access. When an interested party asks 

to be informed APHIS ensures there contact information is added to the list of interested 

stakeholders. Each local office works to inform interested parties of the availability of an EA for 

comment. Any omission of an interested party is not intentional. Contact information 

for Nevada’s EA’s is on the cover page of the Draft EA’s. Also included with the distribution of 
104

the EA’s was a letter of notice clearly detailing the 30 day comment period extending from 

March 6th through April 7th. 

APHIS is not aware of the direct personnel communication cited by the commenter. APHIS 

personnel are engaged in a wide variety of activities to protect American agriculture and not 

every staff member is completely informed about the details of the Grasshopper Program NEPA 

compliance procedures.

Comment 60

APHIS received the following comment, “there is no information on when the comment period 

opened or closed on the EAs provided on the webpage.”

The local offices emailed public notices to a list of stakeholders that they have collected over the 

years and they also announce the open comment period in the local media. Those notices have 

the link for the EA’s for comment and the point of contact. In an attempt to be more transparent, 

we have put all of our EA’s on to the website for people to access. When an interested party asks 

to be informed, APHIS ensures there contact information is added to the list of interested 

stakeholders. Each local office works to inform interested parties of the availability of an EA for 

comment. Any omission of an interested party is not intentional.

Contact information for the Nevada state office is on the cover page of the Draft EA. Included 

with the distribution of the EAs was a notice of public comment clearly stating the website 

and address for EA documents and where to send comments and the closing date of April 7th, 

2020. Public meetings were held February 24th through the 27th to discuss Draft EA. 

Comment 61

APHIS received the following comment, “the EAs are dated February 21, so that when we did

see them we erroneously believed that we had missed the comment deadline. Had we not been 

persistent in following up to ascertain the actual posting date and comment period closing date, 

we could have easily missed the opportunity to comment.”

See previous response.

Comment 62

APHIS received the following comment, “APHIS has failed to comport with NEPA’s threshold 

requirements.”

APHIS did not fail to perform NEPA’s threshold requirements for public outreach and 

engagement, but rather exceeded them. See previous comments concerning how APHIS informed 

interested parties of the availability of EAs for public comment, including public meetings, where 

to send comments, and the closing date for the comment period.

Comment 63

APHIS received the following comment, “The Draft EAs further limit public participation by 

failing to post notices in the Federal Register or on regulations.gov, unlike earlier versions of the 

environmental review.”
105

APHIS further involves the public in the scoping process by the publication of notices of 

availability for EAs and a Findings of No Significant Impact (FONSIs). When an individual State 

level EA is written, a notice is published in the legal section of the local newspaper, advertising 

the availability of the EA during an open comment period. The notices published in local 

newspapers was conducted in accordance with APHIS’ NEPA Implementation Procedures, 

372.7 (b)(3), Notification of the availability of environmental assessments and findings of no 

significant impact for proposed activities will be published in the FEDERAL REGISTER, unless 

it is determined that the effects of the action are primarily of regional or local concern. Where 

the effects of the action are primarily of regional or local concern, notice will normally be 

provided through publication in a local or area newspaper of general circulation and/or the 

procedures implementing Executive Order 12372, “Intergovernmental Review of Federal 

Programs.”

Public involvement under the CEQ Regulations for Implementing the Procedural Provisions of 

NEPA distinguishes federal actions with effects of national concern from those with effects 

primarily of local concern (40 CFR 1506.6). Our EIS process for the GMC program was 

published in the Federal Register (APHIS-2016-0045), and met all applicable notice and 

comment requirements for a federal action with effects of national concern. This process 

provided individuals and national groups the ability to participate in the development of 

alternatives and provide comment. Our subsequent state-based actions have the potential for 

effects of local concern, and we publish them according to the provisions that apply to federal 

actions with effects primarily of local concern. This includes the USDA APHIS NEPA 

Implementation Procedures, which allows for EAs and FONSIs where the effects of an action are 

primarily of regional or local concern to normally provide publication in a local or area 

newspaper of general circulation (7 CFR 372.7(b)(3)). These publications provide potentially 

locally-affected individuals an additional opportunity to provide input into the decision-making 

process. Some states also provide additional opportunities for local public involvement, such as 

public meetings.

In Nevada, Draft EA’s are emailed upon request to the public, stakeholders, etc. Tribal 

stakeholders copies of EA’s are delivered via mail annually. 

Comment 64

APHIS received the following comment, “[The Center for Biological Diversity] have been 

informed that there was notice in local newspapers. This local notice is insufficient as it excludes 

countless other interested parties.”

See previous response

Comment 65

APHIS received the following comment, “APHIS has failed to meet NEPAs requirements for 

public involvement in these EAs.”

APHIS also notes CEQ guidance for public involvement in the NEPA process of agencies, 

“A Citizen’s Guide to the NEPA” states: “When preparing an EA, the agency has discretion as 
106

to the level of public involvement. The CEQ regulations state that the agency shall involve 

environmental agencies, applicants, and the public, to the extent practicable, in preparing EAs. 

Sometimes agencies will choose to mirror the scoping and public comment periods that are 

found in the EIS process. In other situations, agencies make the EA and a draft FONSI available 

to interested members of the public”.

Some agencies, such as the Army, require that interested parties be notified of the decision to 

prepare an EA, and the Army also makes the EA publicly available. Some agencies keep a 

notification list of parties interested in a particular kind of action or in all agency actions. Other 

agencies simply prepare the EA.

Contact information for the Nevada state office is on the cover page of the Draft EA’s.

The notice of public comment clearly stated the website and Address for EA documents and 

where to send comments and the closing date of April 7th, 2020.

Public meetings were held February 24th, 25th, 26th, and 27th to discuss Draft EA and local 

concerns. A notice of public comment was released with the Draft EA’s outlining the comment 

period beginning March 6th, 2020 and expired April 7th, 2020.

Comment 66

APHIS received the following comment, “the range of alternatives offered by APHIS is woefully 

inadequate.”

APHIS structured and analyzed the risk of the substantial program alternatives available to the 

agency.

Comment 67

APHIS received the following comment, “[The alternatives] are, “No Action,” “Insecticide 

Applications at Conventional Rates or Reduced Agent Area Treatments with Adaptive 

Management Strategy” (preferred alternative). While the RAATs are an improvement over 

conventional approval rates, this alternative should actually be two, one, Insecticide Applications 

at Conventional Rates and two, Reduced Agent Area Treatments with Adaptive Management 

Strategy. Lumping the two together means that supporting this alternative could mean pesticide 

application at conventional rates without RAATs. APHIS must break these into different 

alternatives.”

The EA states “Under Alternative A, the No Action alternative, APHIS would not conduct a 

program to suppress grasshopper infestations. Under this alternative, APHIS may opt to provide 

limited technical assistance, but any suppression program would be implemented by a 

Federal land management agency, a State agriculture department, a local government, or a 

private group or individual.”

Under Alternative B, the Preferred Alternative, APHIS would manage a grasshopper treatment 

program using potentially any of pesticides and application methods described in the EA 

Alternative B to suppress outbreaks. The grouping of conventional methods and pesticide rates 
107

with the more commonly used RAATs procedures reflects the variety of approaches that the 

agency may need depending on treatment specific circumstances.

Comment 68

APHIS received the following comment, “APHIS does not include an alternative that utilizes 

Integrated Pest Management.”

APHIS technical guidance is part of each alternative proposed, and is not unique to any one 

alternative. An example of APHIS technical guidance is the agency’s work on integrated pest 

management (IPM) for the grasshopper program. IPM for grasshoppers includes biological 

control, chemical control, rangeland and population dynamics, and decision support tools.

APHIS has funded the investigation of various integrated pest management (IPM) strategies for 

the grasshopper program. Congress established the Grasshopper Integrated Pest Management 

(GIPM) to study the feasibility of using IPM for managing grasshoppers.

The major objectives of the APHIS GIPM program were to: 1) manage grasshopper populations 

in study areas, 2) compare the effectiveness of an IPM program for rangeland grasshoppers with 

the effectiveness of a standard chemical control program on a regional scale, 3) determine the 

effectiveness of early sampling in detecting developing grasshopper infestations, 4) quantify 

short- and long-term responses of grasshopper populations to treatments, and 5) develop and 

evaluate new grasshopper suppression techniques that have minimal effects on non-target 

species (Quinn, 2000).

The results for the GIPM program have been provided to managers of public and private 

rangeland including ways to manage grasshopper populations in the long-term, such as livestock 

grazing methods and cultural control by farmers.

APHIS issued the GIPM User Handbook describing biological control, chemical control, 

environmental monitoring and evaluating, modeling and population dynamics, rangeland 

management, decision support tools, and future directions.

Federal and State land management agencies, State agriculture departments, and private groups 

or individuals may carry out a variety of preventative IPM strategies that may reduce the 

potential for grasshopper outbreaks. Some of these activities include grazing management 

practices, cultural and mechanical methods, and prescribe-burning of rangeland areas. These 

techniques have been tried with varying success in rangeland management, and some have been 

associated with the prevention, control, or suppression of harmful grasshopper populations on 

rangeland.

Regardless of the various IPM strategies taken, the primary focus of the risk analysis contained 

in the EAs is on the potential impacts from chemical treatments needed during an outbreak of 

economic importance. While APHIS provides technical expertise regarding grasshopper 

management actions, the responsibility for implementing most land management practices lies 

with other Federal (i.e., BIA, BLM, and USDA’s FS), State, and private land managers.
108

The final EA will be updated to reflect APHIS support for IPM strategies in the grasshopper and 

Mormon cricket suppression program.

Comment 69

APHIS received the following comment, “Given that much of APHIS’s work on grasshopper and 

Mormon cricket suppression is on federal public lands or adjacent to federal public lands 

in Nevada, it only makes sense that it would conform to their IPM mandates in these EAs.”

See previous response. APHIS supports the use of IPM to prevent grasshopper outbreaks on or 

near Federal lands. These actions are and should continue to be considered by agencies as part 

of proper land management. APHIS treatments are a component of the IPM strategies that may 

be employed by Federal land management agencies. APHIS also adheres to any restrictions 

proposed by Federal land management agencies that may be part of their IPM strategies. 

Comment 70

APHIS received the following comment, “APHIS must adopt an alternative that harmonizes its 

mandates in regard to grasshoppers and Mormon crickets with the IPM mandates of the federal 

lands that it operates on.”

See previous response. A Memorandum of Understanding between land management agencies, 

i.e., the Department of Interior’s Bureau of Indian Affairs and Bureau of Land Management, and 

USDA’s Forest Service, indicates that while APHIS provides technical expertise, namely advice, 

regarding grasshopper management actions, the responsibility for implementing most land 

management practices, including IPM measures, lies with other Federal (i.e., BIA, BLM, and 

USDA’s FS), State, and private land managers (page 32 of the 2019 EIS).

Comment 71

APHIS received the following comment, “APHIS must enlist IPM experts to craft an alternative 

that is land-use and pest-specific, using the minimum level of pest suppression necessary, relying 

on prevention, avoidance, monitoring, and suppression techniques in order to decrease pest 

pressure with the least harmful controls possible.”

See comment 67

Comment 72

APHIS received the following comment, “APHIS does not provide a single citation or any other 

evidence to support its assertions that the pesticides proposed to be used ‘pose no risk of direct 

toxicity, carcinogenicity, neurotoxicity, genotoxicity, reproductive toxicity, or developmental 

toxicity.’”

The quote referenced in the comment has been removed from the final EA. The risk analysis in 

the EA is tiered to the two Environmental Impact Statements (2002 and 2019) and the four 

Human Health and Ecological Risk Assessments as described in sections I.C. About this 

Process, II.A. Alternatives (where an internet link to the more in-depth risk analysis documents 

is provided on page 7), in the second paragraph of section IV. Environmental Consequences (a 

link is also provided there), and many other locations in the EA.
109

Comment 73

APHIS received the following comment, “Perhaps APHIS is attempting to claim that because 

‘there is a lack of any adverse health effects reported from these projects.’”

Discussions regarding risk to human health in the EA is based on available data that was 

summarized in the human health and ecological risk assessments that were prepared to support 

the updated EIS published in 2020. APHIS would take into account any adverse effects noted 

during program use of a pesticide however a lack of effects on its own would not be used to make 

a conclusion that there are no adverse health effects.

Comment 74

APHIS received the following comment, “APHIS must conduct an adequate analysis of human 

health effects.”

APHIS prepared and published separate Final Human Health and Ecological Risk Assessments 

for all the pesticides used by the Grasshopper Programs (November 2019).

Adherence to label requirements and additional Program measures designed to reduce exposure 

to workers (e.g., PPE requirements include long-sleeved shirt and long pants and shoes plus 

socks) and the public (e.g., mitigations to protect water sources, mitigations to limit spray drift, 

and restricted-entry intervals) result in low health risk to all human population segments.

Comment 75

APHIS received the following comment, “there is no description of how APHIS plans to identify 

or contact these individuals in order to advise them to avoid treatment areas.”

In areas considered for treatment, State-registered beekeepers and organic producers shall be 

notified in advance of proposed treatments. APHIS will notify residents within treatment areas, 

or their designated representatives, prior to proposed operations, and advise them of the control 

method to be used, proposed method of application, and precautions to be taken.

Comment 76

APHIS received the following comment, “APHIS’s failure conduct any analysis of their impacts 

to human health is a far cry from the level of analysis demanded by NEPA and basic due care for 

public health.”

See responses to comment 73. APHIS prepared and published separate Final Human Health and 

Ecological Risk Assessments for all the pesticides used by the Grasshopper Programs 

(November 2019). These documents were incorporated by reference into the draft EA.

Comment 77

APHIS received the following comment, “APHIS fails to look at the effects of the proposed 

action on migratory birds.”
110

Executive Order 13186 directs Federal agencies taking actions with a measurable negative 

effect on migratory bird populations to develop and implement a Memorandum of Understanding 

with the USFWS that promotes the conservation of migratory bird populations. On August 2, 

2012, a Memorandum of Understanding between APHIS and the USFWS was signed to facilitate 

the implementation of this Executive Order.

Specifically to the grasshopper and Mormon cricket program, APHIS evaluated potential 

impacts to birds in the final EIS and associated human health and ecological risk assessments.

These documents are incorporated by reference into the final EA.

For Nevada, APHIS includes information on migratory birds in their EA in Appendix 3 Table 1.

Effects on migratory birds are discussed during site specific consultation between USFWS and 

the land managers.

Comment 78

APHIS received the following comment, “APHIS needs to take a hard look at the impacts of the 

proposed action, including direct and indirect effects.”

The EA incorporated the analysis from the EIS and associated human health and ecological risk 

assessments into the analysis. The EIS, and in particular, the risk assessments evaluated 

potential indirect effects to non-target organisms, relying on available toxicity data and 

estimates of risk. 

Comment 79

APHIS received the following comment, “A direct effect of not spraying insecticides is abundant 

food for migratory birds. Conversely, a direct effect of spraying is reduced abundance of food for 

insectivorous migratory birds. Another potential direct effect of insecticide spraying is 

poisoning. An example of an indirect effect is the cumulative effect of continuous low level 

pesticide exposure from numerous sites over many years. APHIS must take a hard look at all 

these impacts”.

APHIS prepared and published separate Final Human Health and Ecological Risk Assessments 

for all the pesticides used by the Grasshopper Programs (November 2019).  The risk assessments 

discuss the risk to birds for each program insecticide.  Available laboratory and field effects data 

were used to evaluate risks to birds through direct exposure as well as indirect effects that could 

result from the loss of prey items such as terrestrial arthropods.

Comment 80

APHIS received the following comment, “APHIS’s handling of impacts to non-target species 

and species of concern wholly fails to meet NEPA’s requirement that the agency take a hard look 

at the impacts of its proposed action.”

APHIS prepared and published separate Final Human Health and Ecological Risk Assessments 

for all the pesticides used by the grasshopper and Mormon cricket suppression program 

(November 2019). The EIS and risk assessments evaluated available effects data and risk to non-
111

target species. These documents are incorporated by reference into the final EA. The risk 

assessments provided the basis for summary statements in the EA that is tiered to the EIS.

The U.S. FWS defines "Species of concern" is an informal term that refers to those species which 

may require some conservation actions but which are not threatened with extinction. The 

conservation actions needed will vary depending on the health of the populations and types and 

degree of threats. At one extreme, there may only need to be periodic monitoring of populations 

and threats to the species and its habitat. At the other extreme, a species eventually may require 

listing as a Federal threatened or endangered species and become the subject of a Federal 

recovery program. Species of concern are not provided legal protection under the Endangered 

Species Act, and the use of the term does not necessarily mean that the species will eventually be 

proposed for listing as a threatened or endangered species. The USFWS and APHIS also 

addresses species of concern during broader ESA consultations and that may result in specific 

protections measures observed by the Grasshopper Program. As an example, USDA APHIS 

PPQ has an MOU with BLM, NDOW, NDA, APHIS, and USFWS with regards to insecticide use 

in and around sage grouse habitat.

Comment 81

APHIS received the following comment, the EA cannot be finalized until APHIS actually takes a 

hard look at the impacts on non-target and species of concern.

See previous response. Under USFWS Section 7 Act there is no requirement to consult on 

sensitive species. However, in Nevada when there is concern by land management agencies, 

federal, state, etc.; APHIS has implemented protective measures for species of concern which 

may be closely related to a T&E species. This is a cooperative effort by APHIS between USFWS, 

Tribal Nations, Nevada Department of Wildlife and/or the Requesting Land Management 

agency.

Comment 82

APHIS received the following comment, “APHIS doesn’t even consider many sensitive or 

culturally important species. For example, monarch butterflies fly through Nevada.”

APHIS prepared and published separate Final Human Health and Ecological Risk Assessments 

for all the pesticides used by the Grasshopper Programs (November 2019). The risk assessments 

and EIS considered available field and laboratory data regarding impacts to Lepidoptera, 

including moths and butterflies. 

Comment 83

APHIS received the following comment, “APHIS also doesn’t consider the impacts of spraying 

on the hundreds of native bee species that reside in Nevada, including many that are exceedingly 

rare.”

APHIS works with Tribal, Federal and State land managers and their local biologists, natural 

resource specialists, and range conservationists to implement measures that reduce risks of 

Program treatments to native bees. These measures may include reduced insecticide applications 

associated with RAATS, avoidance measures and use of carbaryl bait, where applicable. APHIS 
112

also prepared and published separate Final Human Health and Ecological Risk Assessments for 

all the pesticides used by the Grasshopper Programs (November 2019). The risk assessments 

summarized available effects data for nontarget species including pollinators.

Comment 84

APHIS received the following comment, “The EAs have not adequately analyzed the cumulative 

impacts of the program with other governmental or private entity actions.”

APHIS discussed the potential of overlapping chemical treatments in the areas where outbreaks 

of grasshoppers have occurred or could occur in the future in the cumulative impacts section of 

the draft EIS, from page 79 to 83. It is unlikely there would be significant overlap between 

APHIS programs and the grasshopper program and coordinated treatments would mitigate 

impacts if there is ever overlap; current label and mitigations minimize significant exposure of 

soil, water, and air to Program insecticides; grasshopper chemical treatments are not expected 

to persist or bioaccumulate in the environment; and, there is a lack of significant routes of 

exposure (page 82 to 83 of draft EIS).

We are unaware of any retreatment that would occur in an area that we have done a treatment.

Generally, the land we treat is a hybrid of BLM rangeland and absentee landowners leasing land 

for grazing. Private landowners do not actively manage that land and, therefore, are not 

expected to be making any other types of chemical treatments. Although APHIS is unaware of 

any, BLM could potentially do herbicide treatments in areas we treat, but they would not treat 

for Grasshopper or Mormon cricket. The cumulative impacts section was updated in the 

final EA to reflect the potential for other land management activities.

Comment 85

APHIS received the following comment, “The EA does not take into account the background 

level of exposure to humans and animals from pesticides and other pollutant sources that exist in 

the environment from other actions or the synergistic effects of the enhanced toxicity that many 

mixtures exhibit.”

The commenter assumes that the rangeland in Nevada which is covered by the Draft EA’s has 

been exposed to pesticides and pollutants and that there is a synergistic effect which enhances 

toxicity to the environment. The land managers that manage the areas covered in the EAs, 

document all pesticide applications. If these remote areas were at risk, the land manager would 

not request APHIS’s services. The activities, or lack thereof, are discussed in the cumulative 

impacts section of the final EA.

Comment 86

APHIS received the following comment, “[the EA] does not account for the range of cumulative 

exposures that would be anticipated. There was no mention of widespread mosquito spraying 

that takes place in many areas.”

Any areas considered for treatment in Nevada would not overlap with any mosquito treatments.

Mosquito treatments in Nevada are not wide spread and are restricted to riparian areas which 

are avoided and buffered in Mormon cricket and grasshopper treatment programs.
113

Comment 87

APHIS received the following comment, “as cattle are grazing these pesticides will be washed 

off their bodies or excreted through waste and contaminate surrounding land and water bodies.”

The labels for Dimilin 2L and Carbaryl 2% bait specify that there is no grazing restrictions.

Any pesticide residues that may be present on forage in treated areas after treatment is typically 

metabolized and excreted as metabolites that have lower toxicity than the parent compound. In 

addition, the low application rates employed by APHIS relative to the current maximum labelled 

rates for each Program insecticide would result in very low residues in livestock waste. 

Comment 88

APHIS received the following comment, “A lot of rangeland is adjacent to lands used for plant 

agriculture, and the EAs state that they also aim to protect these agricultural lands. These areas 

generally have a high potential for crossover contamination through drift or runoff of pesticides. 

Large quantities of pesticides, including insecticides and fungicides that may be synergistic with 

the insecticides included in the EAs, may be used on these lands. In addition, herbicide use on 

crops already significantly impacts insects by destroying habitat and food sources in agricultural 

lands”.

Nevada has never included agriculture land in previous spray programs in the past and does not 

have plans to include agriculture land in the future. While we may focus on rangeland 

surrounding agriculture land, there is often untreated areas between the two due to land 

ownership patterns common in Nevada.

The pesticide labels which APHIS uses prohibits their use on specific crops, agricultural lands 

etc. The labels and use rates are specific to rangeland or pasture land use.

Comment 89

APHIS received the following comment, “None of these issues were disclosed or analyzed in the 

Draft EIS and add to the already large cumulative exposures from pesticides used in 1) the 

boll weevil eradication program, 2) fruit fly cooperative eradication program, 3) the gypsy moth 

cooperative eradication program, and 4) invasive plant control”.

The commenter refers to the Draft EIS. The EIS has been finalized and the ROD has been 

signed. The final EIS does address the cumulative exposures from other APHIS programs on a 

programmatic level. The documents in question are the Draft EA’s. The programs mentioned by 

the commenter are not relevant to the Rangeland Grasshopper and Mormon Cricket Suppression 

Program.

There is no geographical overlap in Nevada now or in the foreseeable future between pesticide 

applications of the Grasshopper Program and the pest control programs mentioned by the 

commenter.
114

Comment 90

APHIS received the following comment, “These cumulative exposures can not only adversely 

affect human and environmental health but can also negatively impact biological control 

programs that try to manage insect and weed pests with natural predators”.

The Grasshopper Program personnel are also the lead biocontrol program personnel in 

Nevada. They are very much aware of the locations of biocontrol programs in the state of 

Nevada. Furthermore, Nevada Department of Agriculture works hand in hand with APHIS 

personnel on the grasshopper program. NDA takes GPS coordinates and maps all biocontrol 

areas they work to establish. The state entomologist is aware of all biocontrol locations that 

would overlap with any proposed treatments and modifications to the block would be made. All 

grasshopper treatments are coordinated with the land managers and other non-grasshopper 

programs are discussed if the land managers are concerned about an overlap with other 

programs. In Nevada, there never has been an overlap of grasshopper treatments and any 

biocontrol program areas. The final EA was updated to reflect the lack of overlap between 

biocontrol activities and Program treatments.

Comment 91

APHIS received the following comment, “How these pesticides act in conjunction with one 

another to additively or synergistically increase toxicity is not discussed and no mitigation 

measures were proposed. Therefore, APHIS must fully analyze the impacts from cumulative 

exposures and identify ways in which risk can be mitigated or prohibited”.

The Grasshopper Program does not apply treatments more than once per year to any rangeland 

area. Therefore, synergistic or additive toxicity between program applied insecticides is not 

possible. Cumulative exposures from pesticides applied by external parties are not expected in 

most cases due to coordination between APHIS, land managers and other cooperators. This 

coordination typically would eliminate the possibility of multiple pesticide applications per year. 

The EA details many procedures APHIS employs to mitigate risk.

Comment 92

APHIS received the following comment, “The project is vague and ill-defined, it improperly 

precludes the disclosure of environmental effects because the information on the project and its 

impacts is incomplete”.

The proposed Grasshopper treatment program described in the EA could occur within a specific 

area, using a limited number of insecticides and application methods. The environmental 

consequences of suppressing or not suppressing grasshopper infestations on multiple ecological 

parameters of the treatment areas are thoroughly described in the EA and other programmatic 

risk analysis documents.

Comment 93

APHIS received the following comment, “APHIS’s explanation of a “level of economic 

infestation,” which is the trigger for insecticide spraying, does not give the public any sense 

whatsoever of when that threshold is met. The definition is too vague and ill-defined to meet 

NEPA’s purposes and mandates. The agency could spray with minimal infestation levels if it 
115

saw fit whenever it decided to do so. There must be a more concrete definition that identifies 

specific thresholds that must be met for the agency to determine an economic level of infestation 

has been met”.

APHIS utilizes and provides links to extensive resources for determining when a grasshopper 

outbreak is exceeding IPM thresholds including, “a level of economic infestation”. The Purpose 

and Needs section of the EA and supporting documents adequately define the multiple factors 

that must be evaluated before APHIS decides a treatment is necessary.

The following footnote is in the Draft EAs page 6.

The “economic infestation level” is a measurement of the economic losses caused by a 

particular population level of grasshoppers to the infested rangeland. This value is determined 

on a case-by-case basis with knowledge of many factors including, but not limited to, the 

following: economic use of available forage or crops; grasshopper species, age, and density 

present; rangeland productivity and composition; accessibility and cost of alternative forage; 

and weather patterns. In decision-making, the level of economic infestation is balanced against

the cost of treating to determine an “economic threshold” below which there would not be an 

overall benefit for the treatment. Short-term economic benefits accrue during the years of 

treatments, but additional long-term benefit may accrue and be considered in deciding the total 

value gained by treatment. Additional losses to rangeland habitat and cultural and personal 

values (e.g., aesthetics and cultural resources), although a part of decision-making, are not part 

of the economic values in determining the necessity of treatment.

Comment 94

APHIS received the following comment, “The EA’s description of the preferred alternative that 

includes “reduced agent area treatments” (“RAATs”) is similarly vague and ill defined”.

RAATs has long been in use, is public knowledge, and one of APHIS’s preferred IPM strategies, 

supported by decades of research. Skipping swaths are the most common RAATs choice, leaving 

50% of the suppression area untreated to maximize refugia for non-target arthropods while 

simultaneously inducing target Orthoptera mortality at desired levels. RAATs are also described 

in detail in the final EIS that is incorporated by reference in the EA.

Comment 95

APHIS received the following comment, “It is unclear whether RAATs will even be used and 

how they will be used in the site specific area”.

APHIS’ preferred method of treatment is to use RAATs as a means to reduce program costs and 

potential environmental effects. However the program could decide to apply insecticides at 

conventional rates and total area coverage if a damaging grasshopper infestation warrants that 

level of suppression. An explanation of the uncertainties involved with predicting grasshopper 

populations before they emerge is provided in section I.C. about this process.
116

Comment 96

APHIS received the following comment, “APHIS could use the pesticide at 95% of the labelled 

rate and still call the application a RAAT.”

RAAT’s is defined as Reduced Agent and/or Area Treatments. The current pesticide labels for 

use in the Program do not allow applications at 95% of the labeled rate to be called RAATs.

This information was also summarized in the final EIS. The commenter will find that EPA has 

approved the verbiage for the pesticide labels. The labels clearly state which rates are allowed 

to meet a RAAT rate. In the case of Dimilin 2L label, which clearly states the application rates 

for RAAT’s is 0.75 - 1 ounce per acre. “Use on rangeland only, in a RAAT’s application on early 

instars. A RAAT’s application is an IPM strategy that takes advantage of grasshopper movement 

and conservation biological control to allow Dimilin 2L to be applied on rangeland on a 

reduced treated area and at reduced rates, while sustaining acceptable control.”

The applicator can only use the RAAT’s rate of .75 or 1 ounce per acre. The label rate, if not 

using RAAT’s is 2 ounces/acre. The RAAT’s rate would be 50% of the label rate not 95% of 

labeled rate. In addition, the practice of skipping spray swaths further reduces the pesticide per 

acre rate.

In the case of using Carbaryl 5% bait the label rate is 20-40 lbs. per acre. APHIS uses the 

RAAT’s rate of 10lbs/acre. In the case of Carbaryl 2% bait, the label clearly states for ground 

applications 25 pounds/acre. It clearly states for U.S. Federal Government and State affiliated 

Grasshopper/Mormon Cricket Suppression Programs using aerial applications the rate of 

application is 10 pounds/acre. So clearly the RAAT’s applications are 50% or less than the 

labeled rates.

The RAAT procedures used by the program are flexible to allow for a reduction of pesticide use. 

Typically the RAAT procedures will result in half the amount of pesticide being applied to a 

treatment block than conventional rates and total coverage. Program managers may reduce the 

rate at which the pesticide is sprayed from the aircraft or increase the distance between swaths 

that are sprayed based on factors specific to grasshopper populations being suppressed. It 

should be noted that APHIS average RAAT rates are lower than the labeled RAAT rates further 

reducing pesticide loading into the environment.

Comment 97

APHIS received the following comment, “The agency must give the public a more precise 

definition of when the threshold for spraying has been met (i.e. number of grasshoppers or 

crickets/acre and a full description of the economic interests at stake).”

The commenter is asking for survey data to be submitted to the public, this data is accumulated 

during the nymphal survey season and is not available when compiling the EA’s. APHIS utilizes 

and provides links to extensive resources for determining when a grasshopper outbreak is 

exceeding IPM thresholds including, “a level of economic infestation”. The Purpose and 

Needs section of the EA and supporting documents adequately define the multiple factors that 

must be evaluated before APHIS decides a treatment is necessary. Establishing a treatment 

threshold based on the number of grasshoppers ignores a variety of factors that must be 
117

considered by program managers before treatments. Some examples include how voracious the 

individual species are that compose a grasshopper infestation and the hardiness of rangeland 

vegetation within a proposed treatment block. These factors are also discussed in the recently 

published final EIS and are incorporated by reference in the final EA.

See previous responses for economic thresholds.

Comment 98

APHIS received the following comment, “APHIS must also convey what metrics will be used to 

determine the area that will be sprayed in any given outbreak”.

The size and exact configuration of a treatment block cannot be forecast prior to the emergence 

of the grasshoppers, requests from land managers and other cooperators, and other 

environmental considerations such as buffers from water and sensitive species. The 

program procedures and mitigation measures are adequately described in the EA and 

supporting documents.

APHIS is unable to predict exactly what areas will be treated before conducting surveys and 

completing the EA. For ground applications, the terrain is key to be able to treat safely.  If the 

terrain is too rough to safely drive a UTV, then the area is not treated even though other factors 

warrant a treatment. There are many variables taken into account before an area is treated.  

Another factor that must be considered is the movement of populations.  If for any number of 

reasons, a treatment can be delayed there is a risk that, depending on species, the boundaries will 

have to be readjusted to account for the movement of populations. 

For example, it is documented that Melanoplus sanguinipes, the Migratory Grasshopper can 

swarm and fly up to 5-10 miles normally. The longest migrations recorded in 1938 were made 

by swarms that traveled from northeastern South Dakota to the southwestern corner of 

Saskatchewan, a distance of 575 miles (Pfadt 1994). This is why it is critical to have a rapid 

response to outbreaks. The planning and logistics is critical and cannot be documented and 

accounted for in the NEPA process. Population dynamics of grasshoppers and Mormon crickets 

are fluid and responses have to be adaptable to the most current assessments to ensure 

successful suppression treatments while minimizing environmental impacts. 

Comment 99

APHIS received the following comment, “The agency must accurately and comprehensively 

disclose and analyze the range of rare, sensitive, threatened, and endangered species, ecological 

areas, communities, Native American gathering grounds and sensitive receptors that could 

potentially be significantly affected by the proposed project” Without this baseline data the EA 

cannot disclose the environmental effects of the project”. 

These sensitive sites are not publicized by the land manger or Tribal nations. In the request for 

treatment letters and in site specific consultation with the land owners/managers, APHIS is made 

aware of and adheres to protective measures agreed upon. T&E species are analyzed during 

the USFWS Section 7 consultations. APHIS adheres to protective measures which have been 

agreed upon with USFWS and addressed in the letters of concurrence.  APHIS also works with 
118

Federal and State land managing agencies to protect other sensitive resources managed on their 

lands. 

APHIS adequately summarized available data for current baseline conditions in the draft 

EA. This includes cultural resources as well as the potential for any overlap of federally listed 

species with the proposed areas of treatment.

Comment 100

APHIS received the following comment, “APHIS’s description of the environmental effects of 

the pesticides at issue failed to properly capture many of their environmental effects”.

APHIS prepared and published separate Final Human Health and Ecological Risk Assessments 

for all the pesticides used by the Grasshopper Programs (November 2019). These documents and 

the associated final EIS are incorporated by reference.

Comment 101

APHIS received the following comment, “Long-term exposure to carbaryl is associated with

decreased egg production and fertility in birds”.

APHIS would make a single application per year to a treatment area, and could apply 

insecticide at an APHIS rate conventionally used for grasshopper suppression treatments, or 

more typically as reduced agent area treatments (RAATs). Carbaryl has a reported half-life on 

vegetation of three to ten days, therefore long-term exposure to birds is not anticipated.

Carbaryl is practically nontoxic to birds on both an acute oral exposure (LD50 >2,000 mg/kg) 

and subacute dietary exposure basis (LC50 >5,000 mg/kg of diet). In addition, no chronic effects 

were observed at a dietary exposure of 300 mg/kg of diet.

Comment 102

APHIS received the following comment, “Carbaryl is considered moderately toxic to mammals 

with decreased pup survival being the most sensitive effect”.

APHIS would make a single application per year to a treatment area, and could apply 

insecticide at an APHIS rate conventionally used for grasshopper suppression treatments, or 

more typically as reduced agent area treatments (RAATs). Carbaryl has a reported half-life on 

vegetation of three to ten days, therefore the chronic exposure to mammals that resulted in 

decreased pup survival is not anticipated.

Comment 103

APHIS received the following comment, “EPA has designated carbaryl as “highly toxic” to bees 

on a short-term exposure basis and ranged from moderately to highly toxic to other insects, mites 

and spiders”.

Although the Grasshopper Program has used the liquid formulation of carbaryl in the past, 

nearly all carbaryl applications this year and for the foreseeable future are likely to be a bait. 

The potential exposures of bees and other pollinators to carbaryl bait are minimal. The risks of 

carbaryl to bees and other non-target organisms are summarized in the human health and 
119

ecological risk assessment that was prepared to support the final EIS. This analysis is 

incorporated by reference into the final EA.

Comment 104

APHIS received the following comment, “Carbaryl is considered “highly toxic” to certain 

species of fish when exposed to short-term bursts and can reduce the number of eggs spawned 

when fish are exposed to lower levels over a longer period of time”.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Carbaryl Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. Comparison of the distribution of 

acute, sublethal and chronic effects data for fish to the residues estimated using ground and 

aerial ultra-low volume spray and bait applications show that the range of residues do not 

overlap with acute toxicity values, suggesting there is no acute risk to fish species. APHIS 

determined there is some overlap with chronic and sublethal effect values and estimated 

residues. However, carbaryl half-lives in water are typically short and with the proposed one 

time application chronic exposure and risk to fish is not anticipated. Effects from consumption of 

contaminated prey are also not expected to be a significant pathway of exposure, based on the 

low residues and low bioconcentration factor values reported for carbaryl.

APHIS guidelines to buffer bodies of water, streams and rivers were addressed in appendix 1 of 

Draft EA’s. The USFWS Section 7 consultations and USFWS letters of concurrence all reduce 

the exposure to fish species.

Comment 105

APHIS received the following comments, “Carbaryl has been designated “very highly toxic” to 

aquatic invertebrates on an acute exposure basis by the EPA and mesocosm studies that analyze 

how the pesticide affects aquatic community structure have found significant negative effects at 

low levels”.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Carbaryl Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. The risk assessment summarizes the 

available laboratory and field effects data for aquatic invertebrates and carbaryl.  The risk 

assessment also summarized the potential exposure and risk to aquatic invertebrates.  The EIS 

and carbaryl risk assessment are incorporated by reference into the EAs.

Comment 106

APHIS received the following comment, “The EPA identified potential interactions between 

carbaryl and the androgen pathway in fish, indicating that carbaryl is an endocrine disruptor in 

male aquatic vertebrates”.

Carbaryl half-lives in water are typically short and with the proposed one time application 

chronic exposure and endocrine disruption risk to fish is not anticipated. Effects from 

consumption of contaminated prey are also not expected to be a significant pathway of exposure, 

based on the low residues and low bioconcentration factor values reported for carbaryl. Chronic 

risk is also a conservative estimate because chronic toxicity data is based on long-term 
120

exposures that what would not be expected to occur from a single application, based on the 

environmental fate of carbaryl in aquatic environments.

Comment 107

APHIS received the following comment, “On March 12, 2020, the EPA released a draft 

biological opinion finding that carbaryl is likely to adversely affect 1542 out of 1745, or 86% 

percent of all listed species in the U.S. and 713 out of 776 designated critical species’ habitats 

across the U.S.”.

The Endangered Species Act section 7 pesticide consultation process between the U.S. Fish and 

Wildlife Service and the National Marine Fisheries Service (the Services, collectively) and the 

EPA specifically concerns FIFRA pesticide registration and reregistration in the United States, 

including all registered uses of a pesticide. The state-level Biological Assessments for APHIS 

invasive species programs are separate from any consultations conducted in association with 

pesticide registration and reregistration process.

The Agricultural Improvement Act of 2018 (Farm Bill) created a partnership between USDA, 

EPA, the Services, and the Council on Environmental Quality to improve the consultation 

process for pesticide registration and reregistration. USDA is committed to working to ensure 

consultations are conducted in a timely, transparent manner and based on the best available 

science. The Revised Method for National Level Listed Species Biological Evaluations of 

Conventional Pesticides provides a directionally improved path to ensuring that pesticides can 

continue to be used safely for agricultural production with minimal impacts to threatened and 

endangered species.

APHIS provided information about use of carbaryl to EPA for the FIFRA consultation for 

carbaryl. The Grasshopper Program use of carbaryl has in the past comprised substantially less 

than 1% of the percent crop treated (PCT) for rangeland use of carbaryl. This is the case for the 

reasonably foreseeable future. For rangeland, in the EPA BE, the Grasshopper Program’s very 

low usage was rounded up to <1% PCT, which gives an overestimate of rangeland acres treated 

and thus endangered species risk. APHIS use of carbaryl is even smaller compared to all uses of 

carbaryl nationwide. Further, the Grasshopper Program consults directly with the Services to 

ensure program activities do not adversely affect protected species or their critical habitat.

Comment 108

APHIS received the following comment, “EPA found many Nevada species were likely to be 

adversely affected. This is a chemical far too toxic for APHIS to consider using across wide 

swaths of land in Nevada”.

Carbaryl is presently approved by the EPA and registered in Nevada. The APHIS 

proposed use for carbaryl in Nevada is not proposed for use across wide swaths of land 

in Nevada but in limited areas of rangeland that require a suppression treatment, most likely as 

a bait treatment. It should be noted that the current labeled uses for carbaryl grasshopper 

treatments are at much higher labels and can be applied with more frequency than what APHIS 

is proposing for use in Nevada. In addition carbaryl use by the Program is minor compared to 

the preferred alternative diflubenzuron. APHIS has evaluated the risk of carbaryl use in the 
121

Program and in general the conclusions are consistent with other risk assessments 

demonstrating low risk when adhering to label requirements. Additional mitigation measures 

used by APHIS further reduces the risk to human health and the environment.

The NMFS consultation does not apply to species in Nevada since there are no federally listed 

species under NMFS jurisdiction however the information was provided in response to comments 

regarding the final EIS. APHIS submitted a programmatic biological assessment to 

the USFWS in 2015. APHIS is currently working with the USFWS to update and complete the 

biological assessment and receive concurrence. The intent of the programmatic biological 

assessment is to provide consistent mitigation measures for listed species that may co-occur with 

Program treatments. Consultation with the USFWS is still being completed at the local level 

prior to any treatments. No APHIS treatments are made in States without prior concurrence

from the USFWS or NMFS regarding federally-listed species. This information is also 

summarized in the final EIS.

Local USFWS Section 7 consultations were entered into prior to the DRAFT EAs. APHIS 

consulted with the USFWS on federally-listed species that may occur within the county or areas 

where grasshopper and Mormon cricket treatments may be required. APHIS works closely with 

the USFWS to determine the application of protection measures and where those measures 

should be applied prior to any treatments. APHIS also evaluated the potential direct and 

indirect impacts to non-target species which is summarized in the final human health and 

ecological risk assessments for each insecticide. 

Comment 109

APHIS received the following comment, “The European Union banned carbaryl in 2007 due to, 

among other things, “...a high long-term risk for insectivorous birds and a high acute risk to 

herbivorous mammals, a high acute and long-term risk to aquatic organisms and a high risk for 

beneficial arthropods”.

APHIS summarizes the risk of carbaryl to non-target organisms in final human health and 

ecological risk assessment that was part of the recently published final EIS. Available effects 

data and the exposures that would be expected from proposed use in the grasshopper and 

Mormon cricket program are reduced based on mitigation measures (ex. RAATS, aquatic 

buffers) and application methods and formulation types which further reduce risk.

Comment 110

APHIS received the following comments, “Carbaryl is classified as “likely to be carcinogenic to 

humans” based on treatment-related hemangiosarcoma development in mice”.

The levels of carbaryl that caused the above-mentioned effects to mice are above exposure 

concentrations that would be expected to occur for the public as well as workers and applicators 

in the APHIS grasshopper and Mormon cricket suppression program.  The risk to human health 

from carbaryl use, including the proposed APHIS use, have been evaluated by APHIS and are 

discussed in the final human health and ecological risk assessment for carbaryl.  It should be 

noted that other agencies have evaluated the risk to carbaryl at much higher application rates 

than those used in the grasshopper and Mormon cricket program.
122

Comment 111

APHIS received the following comments, “EPA has determined that humans can be exposed to 

more than 4 times the amount of carbaryl known to cause neurotoxicity from some legal uses of 

the pesticide. EPA also found that the current labelled uses of carbaryl may result in neurotoxic 

harms to mixers, loaders and applicators.”

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Carbaryl Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. APHIS evaluated the potential human 

health risks from the proposed use of carbaryl ULV sprays and carbaryl bait applications and 

determined that the risks to human health are low. The lack of risk to human health is based on 

the low probability of human exposure and the favorable environmental fate and effects data.

APHIS treatments are conducted in rural rangeland areas where agriculture is a primary 

economic factor. Rural rangeland areas consist of widely scattered, single dwellings in ranching 

communities with low population density. Risk to the general public from carbaryl ground or 

aerial applications is also expected to be minimal due to the low-population areas proposed 

for treatment, adherence to label requirements, and additional Program measures designed to 

reduce exposure to the public.

APHIS is not obligated to analyze the risk posed by all legal uses of carbaryl, but rather the 

Grasshopper Program formulations and application rates.

The proposed use of carbaryl as a ULV spray or a bait and adherence to label requirements 

substantially reduces the potential for exposure to humans. APHIS does not expect adverse 

health risks to workers because of the low potential for exposure to carbaryl when applied 

according to label directions and the use of personal protective equipment. APHIS quantified the 

potential risks associated with accidental exposure of carbaryl for workers during mixing, 

loading, and application. The quantitative risk evaluation results indicate no concerns for 

adverse health risk for Program workers from carbaryl applications in accordance with 

program standard operating procedures for safety.

Comment 112

APHIS received the following comment, “EPA has found that all use scenarios 

of chlorantraniliprole can result in direct or indirect effects to all listed species”.

The EPA risk assessment is a screening level ecological risk assessment that evaluated risk 

under a variety of application rates with most being well above use rates proposed in the APHIS 

Grasshopper Program. APHIS prepared a final human health and ecological risk assessment 

that assesses the risk of APHIS Program treatments. The state-level Biological Assessments for 

APHIS invasive species programs are separate from any consultations conducted in association 

with pesticide registration and reregistration process.

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore, any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.
123

Comment 113

APHIS received the following comment, “Chlorantraniliprole is considered “very highly toxic” 

to freshwater invertebrates and EPA found that many uses of it can result in acute and chronic 

harms to aquatic invertebrates. This was the case for both aerial and ground spray applications. 

Sublethal doses can impair locomotion in bees more than seven days post exposure. A 2013 

European Food Safety Authority analysis of chlorantraniliprople found that the use of the 

pesticide poses a high risk to soil macro-organisms, aquatic invertebrates and sediment dwelling 

organisms.” and “APHIS must consider chlorantraniliprole substantial environmental impacts, 

including population level effects”.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Chlorantraniliprole Rangeland Grasshopper 

and Mormon Cricket Suppression Applications is published. The document 

summarizes available effects data and characterizes risk to human health and non-target 

organisms based on the use pattern proposed by the Program. Results from the risk assessment 

suggest low risk of chlorantraniliprole to non-target aquatic organisms and most terrestrial 

invertebrates.

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore, any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.

Comment 114

APHIS received the following comments, “Diflubenzuron is considered “highly” to “very highly 

toxic” to aquatic invertebrates. In a 2018 analysis, EPA found that the registered, labeled uses of 

diflubenzuron may result in freshwater invertebrate exposure at up to 550 times the level known 

to cause harm. Diflubenzuron exposure to honeybees and other pollinators at the larval stage was 

estimated to be more than 500 times the level known to cause harm. Although arthropods are not 

a part of EPA’s ecological risk assessment, the European Food Safety Authority found that 

“Juvenile non-target arthropods were very sensitive to diflubenzuron. Very large in-field nospray buffer zones would be needed to protect nontarget arthropods. There is no reason for 

APHIS to exclude consideration of impacts to arthropods in its analysis of this pesticide.” and 

“APHIS also acknowledges the pollinator impacts but attempts to diminish them without 

providing evidence on how or why they are not significant”.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Diflubenzuron Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. The EPA risk assessment evaluated 

risk to aquatic organisms and pollinators based on application rates, methods of application and 

use patterns that would result in greater exposure and risk to aquatic and terrestrial 

invertebrates.  APHIS evaluated risks to these groups of non-target organisms based on methods 

of application consistent with Program applications and other mitigation measures for 

diflubenzuron.  The exposure potential is reduced compared to label uses due to many factors.  

This includes but is not limited to reduced application rates, one application per season, use of 

RAATs and buffers from aquatic habitats.  APHIS relied on laboratory and field collected data 
124

regarding diflubenzuron effects to aquatic and terrestrial invertebrates to show that risk is low 

for most non-target invertebrates.  

Characterization of risk to aquatic species from Program-specific diflubenzuron applications 

was made by comparing the residue values in the exposure analysis from ground and aerial 

applications to the distribution of available acute and chronic fish toxicity data. Residue values 

were below the distribution of acute and chronic response data, suggesting that direct risk to 

aquatic species is not expected from diflubenzuron applications. More specifically, the 

distribution of aquatic invertebrate toxicity data is above the residues estimated from spray drift 

models for Grasshopper Program ground and aerial applications of diflubenzuron.

The Endangered Species Act section 7 pesticide consultation process between the U.S. Fish and 

Wildlife Service and the National Marine Fisheries Service (the Services, collectively) and the 

EPA specifically concerns FIFRA pesticide registration and reregistration in the United States, 

including all registered uses of a pesticide. The Grasshopper Program treatments employ 

methods and diflubenzuron application rates that result in substantially lower freshwater 

invertebrate exposures than the rate cited by the EPA and the commenter.

The EPA Preliminary Risk Assessment to Support Re-registration Review examines all legal uses 

of diflubenzuron, of which the Grasshopper Program constitutes a small fraction. APHIS is not 

obligated to examine all legal uses of the pesticide, but rather those contemplated by the 

program. The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS 

and Final Human Health and Ecological Risk Assessment for Diflubenzuron Rangeland 

Grasshopper and Mormon Cricket Suppression Applications are published. Characterization of 

risk to aquatic species from diflubenzuron applications was made by comparing the residue 

values in the exposure analysis from ground and aerial applications to the distribution of 

available acute and chronic fish toxicity data. Residue values were below the distribution of 

acute and chronic response data, suggesting that direct risk to aquatic species is not expected 

from diflubenzuron applications. More specifically, the distribution of aquatic invertebrate 

toxicity data is above the residues estimated from spray drift models for Grasshopper Program 

ground and aerial applications of diflubenzuron.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Diflubenzuron Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. The APHIS analysis noted 

Diflubenzuron has low toxicity and risk to some nontarget terrestrial invertebrates, including 

pollinators such as honey bees.

Comment 115

APHIS received the following comment, “APHIS also acknowledges the pollinator impacts but 

attempts to diminish them without providing evidence on how or why they are not significant. It 

does not mention that Nevada is home to an amazing abundance of native bees and pollinators, 

and improperly uses honeybees as a surrogate for pollinators, when native pollinators are far 

more sensitive due to the lack of hive buffering effects. This is not a pesticide that should be 

applied to broad swaths of land. It is highly toxic to far too many species of importance 

in Nevada.”
125

Grasshopper IPM field studies have shown diflubenzuron to have a minimal impact on ants, 

spiders, predatory beetles, and scavenger beetles. There was no significant reduction in 

populations of these species from 7 to 76 days after treatment. Although ant populations 

exhibited declines of up to 50%, these reductions were temporary, and population recovery was 

described as immediate (Catangui et al., 1996). No significant reductions in flying non-target 

arthropods, including honey bees, were reported. Within one year of diflubenzuron 

applications in a rangeland environment, no significant reductions of bee predators, parasites, 

or pollinators were observed for any level of diflubenzuron treatment (Catangui et al., 1996).

Comment 116

APHIS received the following comment, “Diflubenzuron is present in the excreted manure and 

urine of cattle where they range and the cumulative exposure must be considered in accordance 

with the ESA and NEPA’s mandate that an action agency take into account the environmental 

baseline”.

APHIS recognizes that some diflubenzuron resides may be present in urine and feces from cattle 

that feed on forage immediately after diflubenzuron treatment; however this pathway of exposure 

is expected to be minor based on the proposed use pattern of diflubenzuron in the Program. Low 

application rates applied only once per season will reduce the amount of diflubenzuron present 

in manure and urine. In addition some metabolism of diflubenzuron occurs in animals and there 

will be further environmental degradation once excreted. 

Comment 117

APHIS received the following comment, “Malathion is considered “very highly toxic” to all 

aquatic and terrestrial invertebrates, as well as aquatic vertebrates such as fish. In addition 

indirect effects to taxa should be considered.’

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Malathion Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published. The risk assessment summarizes 

available laboratory and field collected aquatic and terrestrial effects data for malathion and 

then estimated risk based on conservative estimates of exposure. APHIS recognizes in the risk 

assessment that malathion can be toxic to sensitive non-target species however the effects have 

to be considered in relation to the potential for exposure to estimate risk as well as historical use 

in the Program which is negligible. 

Comment 118

APHIS received the following comment, “When exposed to malathion for longer periods of 

time, female birds displayed regressed ovaries, reduced number of hatched eggs and enlarged 

gizzards”.

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Malathion Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published.
126

Several reproductive and developmental studies have been conducted with birds. The lowest 

median lethal dose to chicken embryos (eggs) was 3.99 mg per egg for 4-day embryos 

(Greenberg and LaHam, 1969). The median lethal concentration for field applications of 

malathion to mallard duck eggs was found to be 4.7 lbs. a.i./acre (Hoffman and Eastin, 1981). 

This is approximately five times greater than the maximum rate for rangeland grasshopper 

(0.928 lbs. a.i./acre), 7.6 times greater than the maximum APHIS application rate (0.619 

lbs. a.i./acre), and nearly 19 times greater than the average RAATs rate applied by APHIS.

No effect on reproductive capacity of chickens was found at dietary concentrations as high as 

500 ppm in feed (Lillie, 1973). Based on the results from chronic reproduction studies using the 

bobwhite quail and mallard duck, the NOEC values were 110 and 1,200 ppm, respectively. The 

most sensitive endpoint in the quail study was regressed ovaries and reduced egg hatch at the 

next highest test concentration (350 ppm). The effect endpoint in the mallard study was growth 

and egg viability at the 2,400 ppm level Lowest Observed Effect Concentration (LOEC).

APHIS expects that direct avian chronic effects would be minimal for most species. The 

preferred use of RAATs during application reduces these risks by reducing residues on treated 

food items and reducing the probability that they will only feed on contaminated food items. In 

addition, malathion degrades quickly in the environment and residues on food items are not 

expected to persist.

Comment 119

APHIS received the following comments, “Malathion degrades into maloxon, which has been 

shown to be at least 22 times more toxic than the parent molecule”.

Similar to other organophosphate pesticides, malathion inhibits the enzyme AChE in the central 

and/or peripheral nervous system. Malathion is metabolized to malaoxon, which is the 

active AChE inhibiting metabolite. AChE inhibition is through phosphorylation of the serine 

residue at the active site of the enzyme, and leads to accumulation of acetylcholine and 

ultimately neurotoxicity. Malaoxon goes through detoxification with subsequent metabolism. 

Absorption and distribution of malathion and malaoxon are rapid with extensive metabolism and 

no accumulation in tissues.

Carboxylesterase detoxifies malathion and malaoxon to polar and water-soluble compounds for 

excretion. A rat metabolism study showed 80 to 90% of malathion excretion in the urine in the 

first 24 hours of exposure. Mammals are less sensitive to the effects of malathion than insects 

due to greater carboxylesterase activity resulting in less accumulation of malaoxon.

Available aquatic toxicity data show that malaoxon is approximately 1.5 to 6 times more toxic to 

fish and 1.8 to 93 times more toxic to amphibians. FMC (2019) reports that malaoxon is 0.80 to 

2.58 times more toxic to fish than malathion based on data that were determined to meet their

criteria for acceptability. The conversion of malathion to malaoxon in aquatic environments can 

range from approximately 1.8 to 10% (CDPR, 1993; Bavcon et al., 2005; USEPA, 2012a). The 

estimated 24-hour EC50 malaoxon value for C. tentans is 5.4 μg/L.

While APHIS assumed that malaoxon is most likely more toxic to aquatic invertebrates than the 

parent; however, due to its low percentage of occurrence in aquatic systems and its rapid 
127

breakdown, malaoxon is not anticipated to pose a greater aquatic risk when compared to 

malathion.

Comment 120

APHIS received the following comment, “A 2017 EPA biological evaluation also found that the 

use of malathion is likely to adversely affect 1778 out of 1835 listed species in the U.S. and 784 

out of 794 critical species’ habitats across the U.S. These findings were based on methodology 

recommended by the National Academy of Sciences. EPA found many Nevada species were 

likely to be adversely affected, such as the yellow billed cuckoo, Bull trout and 

Steamboat buckwheat, among others. The U.S. Fish and Wildlife Service later drafted a 

biological opinion finding that malathion is likely to jeopardize the continued existence of 1284 

threatened and endangered species. This is an astounding number of jeopardy calls for a single 

pesticide, and makes it even more astounding that APHIS would continue to consider using it for 

grasshopper and cricket control.”

The Endangered Species Act section 7 pesticide consultation process between EPA and the 

Services specifically concerns FIFRA pesticide registration and reregistration in the United 

States, including all registered uses of the pesticide. The Grasshopper Program use of malathion 

comprised nearly none of the percent crop treated for rangeland in the past, and this remains 

APHIS’ expectation for the foreseeable future. Further, the Grasshopper Program consults 

directly with the Services to ensure program activities do not adversely affect protected species 

or their critical habitat.

Comment 121

APHIS received the following comment, “California’s Proposition 65 list of chemicals known to 

cause cancer and has been designated as having suggestive evidence of carcinogenicity by the 

EPA for instances of liver, oral palate mucosa and nasal respiratory epithelium tumor formation 

in mice.”

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and Final 

Human Health and Ecological Risk Assessment for Malathion Rangeland Grasshopper and 

Mormon Cricket Suppression Applications are published.

Comment 122

APHIS received a comment that, “EPA has determined that humans can be exposed to more than 

6 times the amount of malathion known to cause neurotoxicity from some legal uses of the 

pesticide. EPA also found that the current labelled uses of malathion may result in neurotoxic 

harms to those exposed to pesticide drift from aerial applications at labelled rates”. The 

commenter also pointed out that occupational applicators, mixers and loaders can be exposed to 

malathion through inhalation and dermal absorption at levels above what the EPA considers safe 

– even when using required personal protective equipment”

APHIS evaluated the risk to human health, including neurotoxicity data in its finale human 

health and ecological risk assessment.  The risk assessment was prepared based on APHIS use 

patterns and Program mitigations that reduce risk to human health.  APHIS is not obligated to 
128

ensure the EA and supporting documents analyze the risk posed by all legal uses of malathion, 

but rather the Grasshopper Program methods and application rates.

Malathion exposure to the general public is not expected from the program use based on label 

requirements and program standard operating procedures that prevent potential exposure. Only 

protected handlers may be in the area during application, and entry of the general public into 

the treated area is not allowed during the re-entry interval period. APHIS treatments are 

conducted on rural rangelands, where agriculture is a primary economic factor and widely 

scattered dwellings in low population density ranching communities are found. The 

program requires pilots avoiding flights over congested areas, water bodies, and other sensitive 

areas. Aerial applications are not allowed while school buses are operating in the treatment 

area; within 500 feet of schools or recreational facilities; when wind velocity exceeds 10 miles 

per hour (mph) (unless a lower wind speed is required under State law); when air turbulence 

could seriously affect the normal spray pattern; and/or temperature inversions could lead to offsite movement of spray. The Grasshopper Program also notifies residents within treatment 

areas, or their designated representatives, prior to application to reduce the potential for 

incidental exposure.

APHIS acknowledges workers in the program are the most likely human population segment to 

be exposed to malathion during grasshopper treatments. Occupational exposure to malathion 

may occur through inhalation and dermal contact during ground and aerial applications. Direct 

contact exposure from the application of a malathion ULV spray will be minimal with adherence 

to label requirements, the use of personal protective equipment (PPE), general safety hygiene 

practices, and restricted entry intervals into treated areas after application.  EPA estimates of 

risk to workers is based on use patterns and rates that result in greater exposure to malathion 

than would occur in the APHIS program.  APHIS evaluated the risk from program specific uses 

of malathion and demonstrated low risk to applicators.  It should also be noted that historical 

malathion use in the Program is negligible further reducing the potential for any types of human 

health risk.

Comment 123

APHIS received the following comment, “APHIS touts EPA-approval as an indication that the 

pesticides that the agency proposes to use are safe. However, under our nation’s pesticide laws, 

EPA-approval is an indication that use of the pesticide won the agency’s cost-benefit analysis, 

and should not be misconstrued as a finding of safety.”

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and 

human health and ecological risk assessments for pesticides used by the Grasshopper Program 

are published. APHIS does not assert the FIFRA registration of the pesticides by the EPA 

demonstrates that the Grasshopper Program uses are safe. Instead the extensive risk analysis 

published by APHIS considered whether the suppression of grasshopper population will have 

significant environmental impacts, in accordance with NEPA.

Comment 124

APHIS received the following comment, “APHIS does not discuss or account for how pesticides 

impact overall soil health or the health of any organisms that reside in soil.”
129

The EA provided links to APHIS’ Grasshopper Program webpage where the 2019 EIS and 

HHERA for pesticides used by the Grasshopper Program are published. The HHERA contain 

extensive analysis of pesticide effects on terrestrial vertebrates, many of which reside in soil.

Comment 125

APHIS received the following comment, “Impacts on soil health can impact listed and non-listed 

plants by impacting nutrient cycling, soil oxygenation and soil water retention, as well as listed 

and non-listed animals that rely on plants or soil organisms for their survival.”

The Grasshopper Program applies pesticides in accordance with current label restrictions 

and program operational procedures that are mitigations to minimize significant exposure 

of soil, water, and air to insecticides; grasshopper chemical treatments are not expected to 

persist or bioaccumulate in the environment.  APHIS evaluated these effects in human health and 

ecological risk assessments that were prepared along with the final EIS for the grasshopper and 

Mormon cricket suppression program.

Comment 126

APHIS received the following comment, “Carbaryl was ranked as extremely toxic to earthworms 

in a lab test rating pesticide toxicity from relatively nontoxic, moderately toxic, very toxic, 

extremely toxic, and super toxic.”

The study was a comparison of the toxicology of 45 pesticide to determine the LC50. These 

studies exposed earthworms to varying concentrations of carbaryl to determine toxicological 

endpoints. Based on the extremely high doses, the impact to the survival of earthworms was not 

only unsurprising, but the object of the studies. APHIS would like to note this laboratory dosing 

procedure is not comparable to any exposure levels resulting from the use of carbaryl ultra-low 

volume sprays by the Grasshopper Program.

Comment 127

APHIS received the following comment, “A single application of carbaryl in a field study caused 

a 38% reduction in survival of total Lumbricidae, and a 78% reduction in total earthworms for at 

least 5 weeks.”

APHIS would like to note the “single application” involved applying carbaryl 6 times on a 

weekly interval to the assigned plots at the highest recommended dose (i.e. Sevin at 9.12 mg/m2), 

a rate that is greater than 16 times the Grasshopper ultra-low volume liquid rate (0.56 mg/m2). 

The Grasshopper program only makes one application per year, rather than six weekly 

treatments. Also, the field study found carbaryl significantly inhibited earthworm feeding activity 

for at least three weeks without leading to any earthworm death.

In addition, the 78% reduction in earthworm casts noted in the comment resulted from an 

application of a combination of clothianidin and bifenthrin pesticides.
130

Comment 128

APHIS received the following comment, “Carbaryl significantly impacted the survival or 

population abundance of E. fetida, E. Andrei, Lumbricus terrestris, and Lumbricus rubellus, 

Aporrectodea caliginosa, and Allolobophora chlorotica.”

These studies exposed earthworms to varying concentrations of carbaryl to determine 

toxicological endpoints (NOEC, LC50). Based on the extremely high doses, the impact to the 

survival of earthworms was not only unsurprising, but the object of the studies. For example in 

Lima et. al. 2011, ten adult worms with individual fresh weight between 300 and 600 mg, were 

exposed to different carbaryl concentrations (20, 40, 60, 80, 100 mg/kg). APHIS would like to 

clarify the Grasshopper Program applies carbaryl ultra-low volume spray at a rate of half a 

pound active ingredient per acre.

Comparison of the results of paper contact test with those obtained in soils clearly demonstrates 

that the contact test has no predictive values for the toxicity of an insecticide in soils, though it is 

important for the initial screening of the environmental chemicals. The differences between 

lowest and highest LC50 values of insecticides for M. posthuma and E. fetida in paper contact 

method were only 6.9 and 2.5-fold respectively while in soil they were over 38 and 26-fold. 

These data demonstrated that worms could tolerate higher concentrations in soil than on moist 

filter paper. This difference in the behavior of the insecticide may probably due to the rate of 

diffusion/uptake of insecticide from the medium into the body of the earthworm. It is well 

reported in the literature that insecticides are adsorbed on soil medium through strong binding 

by organic matter contents in soils (Davis, 1971, Van Gestel and Van Dis, 1988). Hence, the 

availability of insecticide for diffusion will be less from the soil than the impregnated filter 

paper. Contact filter paper test can be used as an initial screening technique to assess the 

relative toxicity of chemicals; however it fails to represent the situation in the soil ecosystem. 

Artificial soil test is more representative of the natural environment of earthworms and acute 

toxicity data on several insecticides can be used in the ecological risk assessment on soil 

ecosystems.

Comment 129

APHIS received the following comment, “In another study, carbaryl induced an avoidance 

response in E. fetida. Soil structure changes were observed between the control and carbaryl 

treated sites, with higher treatments of carbaryl causing significantly more lumps in the soil due 

to earthworm inactivity.”

The commenter cited a study where worms were rinsed in tap water and transferred to the flasks 

containing 2 ml solution per worm. The flasks were gently tilted every 5 min and the exposure 

was terminated after 30 min. The worms were removed, rinsed in cold tap water and transferred 

to Petri dishes (five worms in each) containing soil but no pesticide. The worms were inspected 

at intervals during 80 days or until all the worms were dead or had recovered. The structure of 

the soil in the Petri dishes was observed in order to get an idea about the ability to work the soil 

after pesticide treatment. APHIS would like to note this laboratory dosing procedure is not 

comparable to any exposure scenario resulting from the use of carbaryl ultra-low volume sprays 

by the Grasshopper Program.
131

Noteably, E. foetida could tolerate high concentrations of carbaryl without dying, although low 

concentrations severely affected its ability to work the soil or to disappear from the soil surface. 

The researchers believe the solutions were equivalent to 64, 32, 16, 8 and 4 mg/kg of pesticide, 

and found that carbaryl did not kill E. foetida in concentrations up to 64 mg/kg, from the 800 

mg/l solution.

The avoidance test is a behavioral test with several advantages (simple, quick and cheap) but 

one drawback: this is not a measure of toxicity but rather a measure of repellence 

(Capowiez and Bérard, 2006), and thus is termed ‘measure of habitat modification’. As there is 

not always a direct relationship between avoidance and toxicity, an improvement of this test was 

recently proposed by Sanchez-Hernandez (2006).

APHIS would like to clarify the Grasshopper Program applies carbaryl ultra-low volume spray 

at a rate of half a pound active ingredient per acre. If a cubic foot of rangeland soil weighs 75 

pounds, 1 acre (43,560 ft.2) of soil two inches deep would weigh 544,500 pounds, or 246,981 

kilograms. The maximum rate used by the Grasshopper Program to apply carbaryl as an ultralow volume spray is half a pound (226796 mg) active ingredient per acre. Therefore, the 

maximum concentration of 0.92 mg carbaryl spray per kg of soil could result from program 

applications. However, this analysis assumes none of the foliar spray settled on vegetation, and 

all of the carbaryl is instantaneously absorbed into the top two inches of soil. In addition, this 

maximum concentration was less than the lowest concentration which the researchers 

determined has significant effects on the reduction of the P. excavatus hatching rate (1.51 mg 

carbaryl per kg of soil). 

Comment 130

APHIS received the following comment, “Carbaryl negatively affected the biomass of E. Andrei, 

Perionyx excavates, total earthworms, and Lumbricus terrestris at a tenth of the recommended 

dose.”

The carbaryl concentrations used for each test species was chosen based on the LC50/EC50 

previously carried out and reported by Lima et al. (2011). This was also a toxicological endpoint 

study where the acute toxicity was determined by exposing the worms to a nominal concentration 

range of 20 to 100 mg/kg of technical grade carbaryl. The application rate was 850 grams per 

hectare of Sevin L85 which is equal to 1.12 pounds active ingredient carbaryl per acre, 

compared with Sevin XLR which is 44.1 % applied at half a pound active ingredient per acre by 

the Grasshopper Program.

This study was primarily designed to validate the production of casts by earthworms as a 

biomarker for behavioral effects. While the significant effects in earthworm weight observed at 

low concentrations of carbaryl are concerning, Grasshopper program applications of foliar 

sprays are unlikely to result in the subsurface soil becoming saturated at the concentrations 

created in the laboratory.

Comment 131

APHIS received the following comment, “A 60-99% reduction in earthworm biomass and 

density due to carbaryl treatment lasted 20 weeks. Burial of organic matter was also negatively 
132

affected. Casting activity of earthworms was reduced by 90%, and 71% and 81% after 3 and 5 

weeks, respectively.”

The researchers made two applications of carbaryl at a rate of 8 lbs. a.i./acre, 16 times greater 

than the maximum spray rate employed by the Grasshopper Program. The Grasshopper 

Program only makes one application per year. In addition, the foliar spray of ultra-low volume 

carbaryl over rangeland is unlikely to result in subsurface soil concentrations comparable to the 

direct turfgrass application made in this study.

Comment 132

APHIS received the following comment, “Carbaryl negatively affected growth in E. fetida, and 

the feeding rate of Diplocardia spp. Total cast production of L. terrestris was significantly 

impacted at one-tenth of the recommended field rate.”

The lowest test concentration that effected E. fetida resulted from saturation of the test media 

with 25 mg/kg of carbaryl. Another field study found a single application of carbaryl 

significantly inhibited earthworm (Diplocardia spp.) feeding activity for at least three 

weeks without leading to any earthworm death. APHIS would like to note the “single 

application” involved applying carbaryl 6 times on a weekly interval to its assigned plots at the 

highest recommended dose (i.e. Sevin at 9.12 mg/m2), a rate that is greater than 16 times the 

Grasshopper ultra-low volume liquid rate (0.5 lbs a.i./acre). The Grasshopper program only 

makes one application per year, rather than six weekly treatments.

Comment 133

APHIS received the following comment, “Reproduction of E. fetida, 

and Perionyx excavatus was negatively affected, with the hatching rate of P. excavatus reduced 

by 87% at sublethal concentrations lower than the recommended field rate. A total loss of 

burrowing was observed at 4 and 8 mg/kg after 40 minutes and at 1 and 2 mg/kg after 80 

minutes.”

The lowest test concentration that effected E. fetida resulted from saturation of the test media 

with 25 mg/kg of carbaryl. In another study the reduction of the P. excavatus hatching rate was 

observed at a concentration of 1.51 mg carbaryl per kg of soil.

APHIS would like to clarify the Grasshopper Program applies carbaryl ultra-low volume spray 

at a rate of half a pound active ingredient per acre. If a cubic foot of rangeland soil weighs 75 

pounds, 1 acre (43,560 ft.2) of soil two inches deep would weigh 544,500 pounds, or 246,981 

kilograms. The maximum rate used by the Grasshopper Program to apply carbaryl as an ultralow volume spray is half a pound (226796 mg) active ingredient per acre. Therefore, the 

maximum concentration of 0.92 mg carbaryl spray per kg of soil could result from program 

applications (0.92 mg/kg). However, this analysis assumes none of the foliar spray settled on 

vegetation, and the carbaryl instantly absorbed into the top two inches of soil, thus mirroring the 

laboratory conditions. In addition, this maximum concentration was less than the lowest 

concentration which the researchers determined has significant effects on the reduction of the 

P. excavatus hatching rate (1.51 mg/kg).
133

Comment 134

APHIS received the following comment, “Morphological abnormalities and histological changes 

in E. andrei and M. posthuma were observed at very low, sublethal doses ranging from 0.24-1.20 

mg/kg and 0.5-1.20 mg/kg, respectively.”

The cited study did not test E. andrei but rather E. fetida a closely related species. The sublethal 

doses were derived from anecdotal observations during filter paper tests where concentrations 

were measured in μg/cm2 not mg/kg. APHIS would also like to note the researcher’s skepticism 

about toxicity tests where the worms are dosed on saturate filter paper. They wrote: 

Comparison of the results of paper contact test with those obtained in soils clearly demonstrates 

that the contact test has no predictive values for the toxicity of an insecticide in soils, though it 

is important for the initial screening of the environmental chemicals. The differences between 

lowest and highest LC50 values of insecticides for M. posthuma and E. fetida in paper contact 

method were only 6.9 and 2.5-fold respectively while in soil they were over 38 and 26-fold. 

These data demonstrated that worms could tolerate higher concentrations in soil than on moist 

filter paper. This difference in the behavior of the insecticide may probably due to the rate of 

diffusion/uptake of insecticide from the medium into the body of the earthworm. It is well 

reported in the literature that insecticides are adsorbed on soil medium through strong binding 

by organic matter contents in soils (Davis, 1971, Van Gestel and Van Dis, 1988). Hence, the 

availability of insecticide for diffusion will be less from the soil than the impregnated filter 

paper. Contact filter paper test can be used as an initial screening technique to assess the 

relative toxicity of chemicals; however it fails to represent the situation in the soil ecosystem. 

Artificial soil test is more representative of natural environment of earthworms and acute 

toxicity data on several insecticides can be used in the ecological risk assessment on soil 

ecosystem.

Comment 135

APHIS received the following comment, “Carbaryl impacted multiple biochemical biomarkers 

in E. andrei, including Acetylcholinesterase (AChE), methoxyresorufin-O-deethylase (MROD), 

and NADH and NADPH red cytochrome reductase.”

This study exposed earthworms to carbaryl in artificial soil at concentrations of 12, 25 and 50 

mg/kg. The research showed that carbaryl inhibited biotransformation enzyme activities but did 

not induce oxidative stress. Since carbaryl is a cholinesterases inhibitor changes detected in 

acetylcholinesterase activities were not surprising. The acetylcholinesterase activity reduction 

was not complete and the residual activity was stable whatever the dose or the exposure duration 

because of the presence in E. andrei of a non-inhibited, non-specific cholinesterases.

APHIS would like to note the lowest tested soil concentration of carbaryl that caused these 

effects (12 mg/kg) is approximately 12 times greater than the hypothetical concentrations that 

could result from Grasshopper Program treatments where none of the foliar ultra-low volume 

spray settles on vegetation, and the chemical is instantly and uniformly mixed into the top two 

inches of soil.
134

Comment 136

APHIS received the following comment, “AChE activity was inhibited in E. fetida in two 

studies, one of which resulted in muscular paralysis that directly impacted earthworm burrowing 

capabilities.”

In the first study, carbaryl stock solution was prepared in acetone and water to yield final 

concentrations of 1, 2, 4 and 8 parts per million. Five earthworms were individually exposed for 

5, 10, 20, 40 and 80 minute intervals in a 50ml beaker containing 2.0ml of various 

concentrations of test solution. The researchers asserted the test concentrations used in the study 

were close to expected residues in the soil without any evidence or analysis as proof. They also 

used higher concentrations to exert significant inhibition of AChE activity and loss of burrowing 

in earthworms for establishing a dose effect “correlationship”. These higher exposures occurred 

after the individual worms were rinsed in tap water, their borrowing rate was measured, 

they were rinsed again, then placed back into the solution. Needless to say this systematic dosing 

in a pesticide solution does not match any exposure levels that could result from the application 

of ultra-low volume sprays.

While the significant reduction in the ability of worms to burrow in soil was clearly evident at 

the lowest test concentration (1 ppm) and the earliest period of exposure (5 min), all worms were 

alive and fully recovered to normal behavior (no tremors, efficient burrowing) 18 hrs. postexposure to 1 ppm carbaryl.

The second study cited by the commenter measured AChE responses in earthworms exposed to 

carbaryl on filter paper and in a soil media. APHIS has previously noted the difficultly 

extrapolating between filter paper toxicological tests to actual exposure scenarios relevant to the 

Grasshopper Program treatments. While the AChE inhibition reached significance after one day 

of exposure to 0.48 mg/kg carbaryl, the researchers did not conclude there was a reduction of 

burrowing capacity. Pure carbaryl was used as a liquid solution, while Zoril 5 was applied as a 

powder spread on the soil. Zoril 5 was thus more abundant on the superficial soil fraction, and 

was immediately in contact with the animals, whereas pure carbaryl penetrated into the soil and 

probably became bioavailable later. APHIS would also like to note the tested application rate of 

17.8 pounds per acre carbaryl 5% powder formulation (Zoril 5), that was estimated to result in a 

concentration of 4.29 mg/kg was nearly twice the maximum Grasshopper Program carbaryl bait 

rate and had no effect on earthworm AChE activity or the lysosomal membrane stability of 

E. andrei.

Comment 137

APHIS received the following comment, “In addition to earthworms, carbaryl negatively 

affected collembola population abundance and reproduction.”

The first and second studies cited by the commenter did not investigate carbaryl or collembola 

(Panda and Sahu, 2004, and Stepić, et al., 2013). The third paper cited used carbaryl as a toxic 

standard for comparison of the effects of other pesticides (Larson et al., 2012). The researchers 

applied carbaryl at a rate of 8.17 lbs. a.i./acre. Researchers conducting the fourth study cited by 

the commenters (Potter et al., 1990) made two applications of carbaryl at the same rate of 8.17 

lbs. a.i./acre, 16 times the maximum rate used by the Grasshopper Program in ultra-low volume 
135

sprays. The Grasshopper Program only makes one application per year. Therefore this study 

used 32 times the carbaryl rate as the program. In addition, the foliar spray of ultra-low volume 

carbaryl over rangeland is unlikely to result in subsurface soil concentrations comparable to the 

direct turfgrass application made in this study.

The next study cited by the commenters (Joy and Chakravorty, 1991) investigated carbaryl 

toxicity to collembola. Adult specimens of Cyphoderus sp. and Xenylla sp. and Lancetoppia sp. 

were exposed to soils saturated with solutions ranging from 0.5 to 10 ml/l. Although they noted 

the standard agricultural doses of carbaryl 50 WP was 6.25 ml/l, the researchers did not provide 

a sufficient description of their methods for APHIS to make a valuable comparison of the 

exposure rates of the collembola in the experiment to potential exposure levels resulting from 

Grasshopper Program treatments.

The commenters cited another study to suggest carbaryl effected collembola reproduction. Three 

nominal concentrations of carbaryl (1, 4 and 7 mg/kg) in soil chemical behavior and toxicity 

were investigated at different temperatures. After 15 days from soil spiking, it was observed that 

carbaryl concentration in soil decreased to 30% and 33% of the initial concentration at the 

temperature extremes of 8 °C and 28 °C, respectively, and 22.8% of the initial concentration 

under a 20 °C temperature regime. The collembola survival and reproduction were 

significantly affected at 4 and 7 mg/kg concentrations, approximately 4 and 7 times greater than 

hypothetical soil concentrations resulting from Grasshopper Program ultra-low volume sprays 

(see previous comments for estimations parameters).

Comment 138

APHIS received the following comments, “Carbaryl also negatively impacted Prostigmata mites, 

and Tiphia vernalis, a wasp that feeds on scarab beetle larvae in the soil.”

In the first study cited carbaryl applied at a rate of 8.18 lbs ai/acre, greater than 16 times the 

Grasshopper Program’s maximum rate, as a toxic standard for comparison of various pesticide 

control efficacy. The effects on oribatid and mesostigmatid mites was not surprising or 

comparable to exposure levels resulting from applications of carbaryl ultra-low volume sprays.

The commenters are mistaken, in that the research cited did not find effects on Tiphia vernalis 

(Helson et al., 1994).

Comment 139

APHIS received the following comment, “Carbaryl can be particularly toxic to ground-nesting 

bees, like Andrena erythronii, Bombus terrestris, and Bombus terricola.”

The commenters cited a toxicology study where carbaryl was applied topically to the thorax of 

the bees to investigate lethal doses and determine the concentration values in units of μg ai/g 

body weight and of μg ai/bee. This dosing method is not comparable to any exposure scenario 

resulting from the Grasshopper Program treatments using ultra-low volume sprays. APHIS 

would like to note that of the six insecticides tested, carbaryl had the second lowest relative 

toxicity, rather than as the commenter characterized being particularly toxic to ground-nesting 

bees. The researchers noted their study does not suggest an inherent, physiological relationship 
136

between size and pesticide susceptibility, and they further suggested that bumble bees may be at 

relatively little risk from carbaryl, contrary to the commenter’s suggestion of particular toxicity 

to Bombus terricola. The researchers elaborated carbaryl previously was not found to have 

significant effects on bumble bees, citing Hansen and Osgood (1984). 

The acute effects of carbaryl on B. terrestris were investigated for ingestion and topical contact 

in another cited study. The researchers found the calculated hazard ratio for oral exposures of 

carbaryl (309) was below the mean (1399) and the median (381) of the 14 pesticides tested and 

reported. Carbaryl was not found to be toxic through topical exposure at the “highest dose 

advised on the label.” The hazard ratio values permit only a comparative evaluation between the 

different active compounds tested.

Comment 140

APHIS received the following comment, “Carbaryl caused 100% mortality in Nomia melanderi 

when exposed to field-rate pesticide residues 3 hours post-application, 97% mortality with 8 

hours post-application, and 78% mortality 2 days post application. Carbaryl was more toxic than 

DDT.”

APHIS does not use DDT during Grasshopper Program treatments and does not agree the 

relative toxicity to carbaryl is a concern. The study cited by the commenter did not test carbaryl 

toxicity on bees, but rather included data from earlier studies. The application rate of carbaryl 

emulated in the earlier studies was 1.0 lbs 80% wettable powder per acre, approximately twice 

the maximum ultra-low volume rate used by the Grasshopper Program. APHIS found the 

literature did not provide sufficient details for a reasonable comparison of the carbaryl 

application methods and rates for additional effects analysis.

Comment 141

APHIS received the following comment, “Bombus impatiens colony vitality (as measured by 

colony weight, worker weight) and the number of workers, honey pots, and brood chambers was 

reduced following carbaryl exposure.”

The researchers noted the confinement of the bee colonies within cages represent a worst case 

scenario in that the workers were caged on the sprayed plots for two or four weeks. Wholecolony consequences of a smaller proportion of the workers foraging on insecticidecontaminated weeds in an open system likely would be less severe. In addition, the researchers 

explained the extent to which an insecticide is hazardous to pollinators is determined by its 

inherent toxicity as well as the formulation and manner in which it is applied (Stark et al. 1995). 

For example, pollen contamination, which can decimate honey bee colonies, may be exacerbated 

by wettable powder or microencapsulated formulations that have high affinity for binding to 

pollen (Johansen et al. 1983).

APHIS would also like to note the direct application of carbaryl to turfgrass at rates ten times 

greater (5.44 lbs ai/acre) than the maximum rate used by the Grasshopper Program 

(0.5 lbs ai/acre) is not comparable to ultra-low volume foliar spray treatments.
137

Comment 142

APHIS received the following comment, “In a laboratory study, chlorantraniliprole negatively 

inhibited the enzymes acetylcholinesterase and glutathione-S-transferase in Eisenia fetida.”

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore, any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.

Comment 143

APHIS received the following comment, “Chlorantraniliprole negatively 

affected Folsomia candida (collembola) reproduction.”

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.

Comment 144

APHIS received the following comment, “Microscopic examination in an avoidance test 

revealed that the collembola were paralyzed from the chlorantraniliprole treatment and couldn't 

migrate, clarifying an observed avoidance at 1 mg/kg, but no avoidance at any higher 

concentrations. The authors note that chlorantraniliprole may be more toxic to non-target 

arthropods closely related to insects than to other soil invertebrates.”

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.

Comment 145

APHIS received the following comment, “In the field, ground-nesting bumble bees (Bombus 

impatiens) treated with chlorantraniliprole consumed less pollen than control bees.”

As previously stated, the Grasshopper Program will not be 

using chlorantraniliprole in Nevada during 2020. Therefore any chlorantraniliprole exposure 

scenarios which the commenter is concerned about are not relevant at this time.

Comment 146

APHIS received the following comment, “Staphylinidae (Coleoptera) population abundance was 

slightly but significantly suppressed.”

As previously stated, the Grasshopper Program will not be using chlorantraniliprole in Nevada 

during 2020. Therefore any chlorantraniliprole exposure scenarios which the commenter is 

concerned about are not relevant at this time.

Comment 147

APHIS received the following comment, “After one application of 

diflubenzuron, myriapoda populations were nearly eradicated (73% reduction), gamasina mites 
138

were reduced by 40%, and uropodina mites were reduced by 57%. Diflubenzuron treatment 

reduced the populations of oribatid mites, prostigmata mites, and soil arthropod larvae, mostly 

comprised of coleoptera and diptera, by nearly 15%.”

The cited research does not suggest Grasshopper Program applications of diflubenzuron will 

result in significant impacts to soil microfauna. The researchers applied diflubenzuron to plots 

and investigated the effects on Collembola, Insecta, Myriapoda, and 4 groups of mites for 6 

months. The observed taxa abundance fluctuated seasonally, but for a majority of taxa no 

significant differences were noticed between the control and exposed plots. The total number of 

microarthropods was insignificantly lower in exposed groups. While myriapods were the only 

taxon that was close to extinction after a single exposure to diflubenzuron the pesticide was 

applied directly to the soil at a rate four times greater than the maximum conventional 

application rate used by the program. The researchers noted their data proved that soil has some 

buffering capacity, and this fact should always be taken into consideration when estimating the 

risk for the environment.

Comment 148

APHIS received the following comment, “In a field study, collembola populations were 

negatively affected by diflubenzuron and did not recover for one and a half years. The 

earthworms, Dendrobaena rubidus and Lumbricus rubellus were reduced in plots treated with 

concentrations of diflubenzuron at half the recommended field rate. Gamasid and oribatid mite 

populations were additionally reduced, and oribatida were observed migrating into deeper soil 

layers to avoid the pesticide.”

The commenters have cited a study where the researchers applied two treatments of 

diflubenzuron wettable powder directly to the forest floor at a rate 37% higher than the 

maximum rate used by the Grasshopper Program. Contrary to the characterization of the 

research findings presented by the commenter, the mean population size of earthworms did 

not differ significantly during the potential effect phase between control and the 137% the 

Grasshopper Program rate treatment plot. The populations of the enchytraeid species 

E. buchholzi, E. minutus, E. norvegicus and M. clavata did not respond to this 137% treatment of 

diflubenzuron applied twice per growing season. While the number of oribatids decreased after 

the application of the insecticides in all experimental plots including the control, these 

differences were only significant in the plot were diflubenzuron was applied directly to the forest 

floor at a rate nearly 14 times greater than the maximum Grasshopper Program rate.

Where Brachychthoniid populations declined significantly in the diflubenzuron treated plots, the 

reductions were in part compensated by changes in numbers of the dominant genus Oppiella.

The researchers explained the half-life of diflubenzuron in soil is reported to range from 1 to 27 

days, which was borne out by their data. Therefore, residue accumulations in the organic layer 

is unlikely if diflubenzuron is only applied once per year.

The researchers acknowledged there could be several potential reasons for differences in 

populations of soil invertebrates between the study plots. First, the plots could differ independent 

of any treatment. APHIS agrees this is a reasonable interpretation because of the small sample 

sizes during the pre-application, potential effect and early recovery data recording phases (I.e. 

four plots including the control, five sample dates, two replicates, n=10). The testing of natural 
139

variation during the 9 month pre-application phase may not have been sufficient. They decided 

to interpret deviations as a response to a treatment, if numbers in the potential effect phase were 

different to those in the other phases in the same plot and to the control in the same phase.

Comment 149

APHIS received the following comment, “Diflubenzuron treatment resulted in a total loss in 

brood production of male Bombus terrestris, and 100% inhibition of egg hatching success and 

larval growth. Transovarial transport and accumulation of the pesticide in deposited eggs 

explained the total loss of reproduction. Abnormal cuticle formation, which can lead to 

mechanical weakness and death, was observed in dead larvae that worker bees were observed 

removing from treated nests.”

The commenters have cited a study where the B. terrestris was directly dosed with diflubenzuron 

to test acute toxicity. Adult worker bees were exposed via contact by topical application and 

orally via drinking sugarwater and by eating pollen. For contact application, 50 μL of the 

aqueous concentration was topically applied to the dorsal thorax of each worker with a 

micropipette. The worker bumblebees were also provided diflubenzuron treated sugar-water for 

drinking for 11 weeks. Bumblebees can also be exposed orally to pollen sprayed until saturation 

with a diflubenzuron concentration. Both the sugar water and pollen were supplied for unlimited 

oral consumption.

While APHIS acknowledges the effects of acute diflubenzuron exposures on the egg hatching and 

larval stages of bumble bees is a concern, the direct dosing conducted by the researchers is not 

comparable to any exposure levels that could result from the Grasshopper Program 

diflubenzuron ultra-low volume spray treatments.

In addition, APHIS would like to note, no acute mortality was observed after topical application, 

nor after oral exposure to treated sugar-water or treated pollen. In all cases, the number of 

dead worker bees in the treated nests over a period of 11 weeks was not above that of the control 

groups using water (0–10%).

Comment 150

APHIS received the following comment, “Multiple studies have observed AChE inhibition in 

earthworms when malathion was applied. Malathion effected the sperm count and viability and 

testicular histology of male E. fetida at sublethal concentrations, potentially impairing population 

abundance.”

APHIS agrees with the commenter that the main acute poisonous effect of malathion is the 

inhibition of the enzyme acetylcholinesterase, and acute poisoning such as was carried out by 

the researchers with direct exposures to high concentrations of the pesticide could occur in many 

types of organisms including earthworms. The direct dosing of earthworms to validate their use 

as toxicological test organisms does not mimic any exposure scenario resulting from the 

Grasshopper Program use of ultra-low volume sprays of malathion.

To further illustrate the disparity between exposures resulting from laboratory toxicity tests and 

grasshopper suppression treatments, APHIS would like to note the lowest tested concentration 
140

was 80 mg/kg of soil. The Grasshopper Program applies malathion ultra-low volume spray at a 

rate of 0.62 pounds active ingredient per acre. If a cubic foot of rangeland soil weighs 75 

pounds, 1 acre (43,560 ft.2) of soil two inches deep would weigh 544,500 pounds, or 246,981 

kilograms. The maximum rate used by the Grasshopper Program to apply malathion as an ultralow volume spray is 0.62 pounds (281227 mg) active ingredient per acre. Therefore, the 

maximum concentration of 1.14 mg malathion spray per kg of soil could result from program 

applications. However, this analysis assumes none of the foliar spray settled on vegetation, and 

the malathion instantly absorbed into the top two inches of soil. This hypothetical soil 

concentration resulting from ultra-low volume sprays should not be compared in a risk analysis 

with the 80 mg/kg tested for sub-lethal effects in the laboratory.

Comment 151

APHIS received the following comment, “In addition to AChE, the biochemical biomarkers 

glutathione-S-transferase, and catalase were also inhibited by malathion in studies with Eisenia 

Andrei. Malathion has also been observed to negatively affect the reproduction of E. andrei.”

The commenters have cited research that confirms malathion inhibits AChE in earthworms. 

While APHIS does not dispute this effect, the agency doubts such effects could result in 

significant impacts. Notably the researchers found the inhibition period suggests lengthening of 

retreatment intervals to 45 days is the appropriate conclusion from the study. APHIS only makes 

one suppression treatment per year to grasshopper infested rangeland.

Comment 152

APHIS received the following comment, “Malathion had a severe effect on AChE activity 

in Drawida willsi. Growth, casting activity, and respiration of D. willsi was negatively affected 

by malathion treatment and did not recover for 75, 60, and 30 days, respectively.”

The commenters have cited research that confirms malathion inhibits AChE in earthworms. 

While APHIS does not dispute this effect, the agency doubts these biomarker effects could result 

in significant impacts.

The study cited by the commenters described malathion’s recommended agricultural dose as 2.7 

to 4.0 kg ai/ha and calculated the equivalent 1.5 to 2.22 mg ai/kg soil, which APHIS would like 

to note are comparable to the concentration estimation provided above. However the toxicity 

results for a single dose of malathion were reported for a concentration of 2.2 mg ai/kg which is 

equivalent to double the dose of 4.0 kg ai/acre, nearly six times the application rate used by the 

Grasshopper Program. 

Comment 153

APHIS received the following comment, “In addition to AChE, the biochemical biomarkers 

glutathione-S-transferase, and catalase were also inhibited by malathion in studies with E. andrei. 

Malathion has also been observed to negatively affect the reproduction of E. andrei.”

The commenters have cited two toxicology studies where earthworms were placed in test tubes 

lined with malathion saturated filter paper to determine acute effect concentrations, extrapolated 

from the biomarker, AChE reduction. The dosing methods and units of ug ai/cm2 are not 
141

comparable to any exposure levels that could result from the application of malathion ultra-low 

sprays by the Grasshopper Program. The study cited by the commenter did not make any 

conclusions regarding malathion affecting reproduction of E. andrei.

Comment 154

APHIS received the following comment, “In a lab test rating the toxicity of 45 pesticides 

to E. fetida, malathion was ranked moderately toxic with an LC50 of 114.4 ug/cm.”

The study cited by the commenter was a comparison of the toxicology of 45 pesticide to 

determine the LC50. These studies exposed earthworms to varying concentrations of carbaryl to 

determine toxicological endpoints. Based on the extremely high doses, the impact to the survival 

of earthworms was not only unsurprising, but the object of the studies. APHIS would like to note 

this laboratory dosing procedure is not comparable to any exposure scenario resulting from the 

use of malathion ultra-low volume sprays by the Grasshopper Program.

Comment 155

APHIS received the following comment, “Malathion caused a 40% decrease in survival of the 

ground-nesting bee, Nomia melanderi.”

The study cited by the commenter did not test malathion toxicity on bees, but rather included 

data from earlier studies. The application rate of malathion emulated in the earlier studies was 

I.0 lb of emulsifiable concentrate per acre, significantly greater than the maximum ultra-low 

volume rate used by the Grasshopper Program. APHIS found the literature did not provide 

sufficient details for a reasonable comparison of the malathion application methods and rates 

for additional effects analysis.

Comment 156

APHIS received the following comment, “The EAs an agency action subject to this consultation 

requirement, must be prepared “concurrently with and integrated with environmental impact 

analyses . . . required by . . . the Endangered Species Act of 1973.”

The commenter has confused the EAs prepared by APHIS for the Grasshopper Program in 

Nevada with other environmental risk analysis documents. See the response to comment 156, 

below.

Comment 157

APHIS received the following comment, “In order to properly provide information to the public 

for commenting on the EIS and the EAs, the section 7 process should be completed prior to the 

completion of NEPA. APHIS must ensure that consultation addresses all species and critical 

habitat that could be directly and indirectly affected by the proposed project.” 

The commenter also states that APHIS has not complied with its responsibilities under Section 7 

of the ESA. Concerns were raised about specific species in Nevada such as the yellow-billed 

cuckoo, Caron wondering skipper, southwestern willow flycatcher, and other listed and sensitive 

species.
142

As stated in the final EIS APHIS has completed programmatic consultation with the National 

Marine Fisheries Service (NMFS). The NMFS consultation does not apply to species 

in Nevada since there are no federally listed species under NMFS jurisdiction however the 

information was provided in response to comments regarding the final EIS. APHIS submitted a 

programmatic biological assessment to the USFWS in 2015. APHIS is currently working with 

the USFWS to update and complete the biological assessment and receive concurrence. The 

intent of the programmatic biological assessment is to provide consistent mitigation measures 

for listed species that may co-occur with Program treatments. Consultation with the USFWS is 

still being completed at the local level prior to any treatments. No APHIS treatments are made in 

States without prior concurrence from the USFWS or NMFS regarding federally-listed 

species. This information is also summarized in the final EIS.

Local USFWS Section 7 consultations were entered into prior to the DRAFT EAs. APHIS 

consulted with the USFWS on federally-listed species that may occur within the county or areas 

where grasshopper and Mormon cricket treatments may be required. APHIS works closely with 

the USFWS to determine the application of protection measures and where those measures 

should be applied prior to any treatments. APHIS also evaluated the potential direct and 

indirect impacts to non-target species which is summarized in the final human health and 

ecological risk assessments for each insecticide. 

Comment 158

APHIS received the comment, “The letter of concurrence relied on by APHIS here does not 

cover 8 out of 16 counties at issue, including Esmeralda, Lincoln, Nye, Carson, Douglas, Lyon, 

Mineral and Storey counties. And, even for the counties covered, the letter of concurrence is 

only for carbaryl, diflubenzuron and malathion, thus the letter of concurrence does not cover the 

activities outlined in the EAs even where it applies to those EAs. APHIS has plainly failed to 

comply with the basic obligations of Section 7 of the ESA for these projects.”

USFWS is aware of this and will remedy it during future concurrences. Proposed treatments are 

exclusively in northern Nevada where our concurrence is covered. Any treatment in Nevada 

would have a site specific consultation with USFWS prior to treatment to ensure there is no 

oversight in consultation.

See comment 29

Comment 159

APHIS received the following comment, “Because the site specific project is vague and fails to 

describe the breadth of cumulative effects it cannot comply with the ESA or NEPA. Any 

discrepancy between the project described in the EAs and the documents provided to the U.S. 

Fish and Wildlife Service must be rectified.”

APHIS believes that the site specific information described in the draft EA is adequate to allow 

completion of Section 7 compliance with the USFWS. Information discussed in the draft EA is 

also shared with the USFWS during consultation so there is no discrepancy between actions 

described in the EA and other documents.
143

Comment 160

APHIS received the following comment, “APHIS would unlawfully be making an irreversible or 

irretrievable commitment of resources if it allows insecticide application on rangeland 

grasshoppers and/or Mormon crickets to occur prior to receipt of a final biological opinion 

from USFWS. APHIS will run afoul of its Section 7 ESA requirements if it chooses to move 

forward, and it will also likely violate the ESA’s prohibition against the take of endangered 

species as described by Section 9 of the statute if it moves forward with this project prior to 

properly completing its Section 7 duties. Even where there is a letter of concurrence, APHIS 

would still fail to comply with the ESA because informal consultation does not authorize the 

incidental take of federally-listed species nor does it authorize the adverse modification or 

destruction of critical habitat.”

APHIS has been able to complete informal consultation with the USFWS regarding the 

Program at the State level. Formal consultation has not been required since the USFWS has 

concurred with the APHIS determinations of not likely to adversely affects, including any 

associated critical habitat. Since APHIS has complied with Section 7 through informal 

consultation, APHIS has not violated Section 9 of the ESA, nor has formal consultation been 

required resulting in a biological opinion.

Comment 161

APHIS received the following comment, “Even where the letter of concurrence applies, it does 

not apply to all the pesticides APHIS is considering using in the EAs, and as USFWS notes in 

the letter of concurrence.” The commenter goes on to state that any actions taken in counties not 

covered, using pesticides not cover, or that may take listed species will be in violation of the 

ESA.

The APHIS Grasshopper Program does not use any pesticides not covered under USFWS 

concurrence. If it is not listed in the concurrence letter it is not used in the field. APHIS does 

not treat in counties not covered in the action areas proposed to the USFWS during Section 7 

consultation.

Comment 162

APHIS has received the following comment, “Grasshopper spraying in or near riparian areas can 

decrease prey populations for these species as well as produce chronic sub-lethal effects as a

result of drift or ingesting pesticide through the insects they consume.”

During the lengthy Local USFWS Section 7 consultations regarding each of the 37 species listed 

as T&E and with critical habitat and all species of concern within those site specific areas, each 

species was discussed point by point. APHIS protective measures were determined using 

the USFWS Recommended Protection Measures for Pesticide Applications in Region 2 of the 

U.S. Fish and Wildlife Service” (USFWS 2007). The USFWS letters of concurrence agree with 

our determinations. In Nevada, the use of ground equipment for localized treatments reduces the 

risk of drift. 
144

Comment 163

APHIS received the following comment, “The Nevada EAs states that this species will be 

covered under mitigation 3 and 10. This mitigation may protect prey for these species, but there 

is no published study on the effects of Dimilin on riparian species or at what distance it can be 

considered to have no effect.”

All mitigation measures are mutually agreed upon during Section 7 consultation with USFWS.

Comment 164

APHIS received the following comment, “Given that these fish all live in stream systems which 

rely to some degree on runoff or snowmelt for water supply, they may be particularly vulnerable 

to aerial applications of insecticides covering a large area which are then washed into occupied 

streams and lakes.”

All treatments buffer all bodies of water to mitigate non target effects. Weather patterns are 

monitored closely during proposed treatments and will not occur if rain is imminent to reduce 

risk of run off.

Comment 165

APHIS received the following comment, “While strong buffers are extremely important, it is 

also important to note that occupied habitat is not always precisely known, and in many 

circumstances, ever changing, especially with climate chaos.”

APHIS is responsible for being the lead agency on the management of grasshoppers and 

Mormon crickets on rangeland. APHIS works with the land manager, county and state officials, 

and USFWS to identify areas where T&E and sensitive species have critical habitat. All 

treatments have a site specific consultation prior to treatment to identify any areas that may 

contain these species.

Comment 166

APHIS received the following comment, “The Warm Springs Amargosa pupfish, Ash Meadows 

Amargosa pupfish, and Ash Meadows speckled dace each occupy spring systems within Ash 

Meadows National Wildlife Refuge managed by the US Fish and Wildlife Service, with the 

Devils Hole pupfish occupying a spring in an exclave of Death Valley National Park managed by 

the National Park Service. These springs are fed from a deep carbonate aquifer, and the flow 

system which feeds these springs has been traced for dozens of miles to the north and east of Ash 

Meadows. Each fish is highly sensitive to perturbations in the aquatic conditions which it is 

adapted to.”

All treatments are sent to USFWS for concurrence prior to treatment. If the managing agency of 

these locations has concerns regarding run off and the proximity of treatment to sensitive areas, 

mitigations measures would be discussed and agreed upon prior to treatment during 

pretreatment consultation with USFWS.
145

Comment 167

APHIS received the following comment, “Both locations are near public rangeland that could be 

sprayed in the event of a grasshopper population boom. Mormon cricket and grasshopper 

population booms and the accompanying pesticide spraying are noted as a threat to this species 

in the 2014 conservation strategy for the Carson wandering skipper. Aerial spraying 

of Dimilin will harm adult and larvae of this species if spray drifts into a populated area.”

APHIS has no proposed treatments in national parks or national wildlife refuges. APHIS would 

require each land managing agency to provide a request for treatment letter before any 

treatments would occur. APHIS does not treat land that is not specifically requested by the land 

manager to be treated.

Comment 168

APHIS received the following comment, “An aerial spray buffer of 1 mile 

for Dimilin (mitigation 2) would be within important potential habitat area for the Carson 

wandering skipper, and thus is insufficient for the protection of this species. An aerial spray 

buffer of 3 miles would (mitigation 6) would remove potentially deadly insecticide from nectar 

and saltgrass locations within the vicinity of extant populations. APHIS must be extremely 

careful with this incredibly narrow endemic species (Ash Meadows naucorid) to ensure that no 

pesticide can enter the groundwater or in any way impact its habitat.”

Mitigation measures are outlined in Appendix C table 3 of the Draft EAs. These mitigation 

measures are agreed upon by USFWS during Section 7 consultation. 

Comment 169

APHIS received the following comment, “There is no data on how carbaryl, dimilin, or 

malathion affects reptiles182 with APHIS attempting to use bird toxicity data to assess reptiles. 

This is a badly flawed extrapolation. Because there is no data on the effects on reptiles, and 

because the desert tortoise is significantly imperiled across its range, precautionary principle 

would dictate that no application of these insecticides occur within desert tortoise habitat.”

APHIS agrees that there is uncertainty in the use of avian toxicity data as a surrogate for reptile 

sensitivity. However in cases where no reptile toxicity data is present avian data can be used to 

approximate potential hazards. APHIS notes this uncertainty in its pesticide human health and 

ecological risk assessments that were completed to support the final EIS. This is also consistent 

with other agencies that have used this avian toxicity data as a surrogate for assessing hazards 

to chemicals. 

In Nevada, the critical habitat for the Desert tortoise was addressed during the local 

USFWS Section 7 consultations. In order to protect this T&E species and critical habitat, 

APHIS agreed with USFWS to exclude a one mile radius of all known occupied habitat from 

APHIS proposed action areas in Nevada. APHIS must also give 5 day notice prior to conducting 

aerial applications of insecticides in occupied desert tortoise habitat to the USFWS Southern 

Nevada Field Office. Thus, APHIS actions would be not likely to adversely affect this T&E 

species in Nevada. The range for this species is primarily in southern Nevada where treatments 

are not expected to occur. 
146

Comment 170

APHIS received the following comment, “There are no current mitigation practices for 

Webber’s ivesia, which is a significant issue for a plant with such a narrow distribution.”

Webber’s ivesia is currently listed on the USFWS T&E species list as a threatened species. In the 

event that Webber’s ivesia occurred in or around the treatment area, site specific consultation 

with USFWS would result in agreed upon mitigation measures prior to treatment. No treatment 

would occur without prior consultation with USFWS. 

Comment 171

APHIS received the following comment, “These mitigation measures can only work if APHIS is 

entirely confident that it knows the entire scope of occupied habitat for these plant species and 

that no changes have occurred.”

As previously mentioned, APHIS is the lead agency responsible for managing Mormon crickets 

and grasshoppers on rangelands. Site specific consultation with USFWS and the land manager 

would be done to identify any areas that have occupied habitat of T&E species or species of 

conservation concern. 

Comment 172

APHIS received the following comment, “While carbaryl is expected to pose minimal risk to 

aquatic and terrestrial plants, application to wet foliage or periods of high humidity may cause 

damage to tender foliage.”

The comment may be referring to the use of liquid formulations of carbaryl. As stated in 

previous responses, Nevada is not proposing the use of liquid formulations of carbaryl. There is 

a very low risk to have enough wet foliage or high humidity to produce enough dew in Nevada.

In addition available toxicity data suggests that effects to terrestrial plants would not occur at 

the proposed use rates

Comment 173

APHIS received the following comment, “[The commenter] would like to see burrowing owl 

addressed more directly in these documents since they are a sensitive species and rely heavily on 

grasshoppers/crickets for prey.

Burrowing owls are addressed as a species of conservation concern under the Migratory 

Bird Treaty Act. The grasshopper populations burrowing owl’s prey on are reduced but not 

eliminated. The owls will shift their diet to other insects that are not affected by grasshopper 

treatments either because of biology or the use of RAATs. Program effects on burrowing owls 

would be no more severe than piping plovers or lesser prairie chickens. 

Comment 174

APHIS received the following comment, “It's also a bit confusing to see species that don't exist 

in NV addressed in EAs specific to NV.”

See comment 29