Asian Citrus Psyllid 

Control Research 

Project 

Hidalgo County, Texas 

Environmental Assessment 

January 2009 

United States 

Department of 

Agriculture 

Marketing and 

Regulatory 

Programs 

Animal and 

Plant Health 

Inspection 

Service 
Asian Citrus Psyllid 

Control Research Project 

Hidalgo County, Texas 

Environmental Assessment 

January 2009 

Agency Contact: 

Stephen Poe 

Senior Operations Officer 

Emergency and Domestic Programs 

Plant Protection and Quarantine 

Animal and Plant Health Inspection Service 

U.S. Department of Agriculture 

4700 River Road, Unit 134 

Riverdale, MD 20737 

__________________________________________________________ 

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its 

programs and activities on the basis of race, color, national origin, sex, 

religion, age, disability, political beliefs, sexual orientation, or marital or family 

status. (Not all prohibited bases apply to all programs.) Persons with 

disabilities who require alternative means for communication of program 

information (Braille, large print, audiotape, etc.) should contact USDA’S 

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

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, 

Room 326–W, Whitten Building, 1400 Independence Avenue, SW, Washington, 

DC 20250–9410 or call (202) 720–5964 (voice and TDD). USDA is an equal 

opportunity provider and employer. 

__________________________________________________________ 

Mention of companies or commercial products in this report does not imply 

recommendation or endorsement by the U.S. Department of Agriculture over 

others not mentioned. USDA neither guarantees nor warrants the standard of 

any product mentioned. Product names are mentioned solely 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 or other wildlife—if they are not handled or applied 

properly. Use all pesticides selectively and carefully. Follow recommended 

practices for the disposal of surplus pesticides and pesticide containers.

United States 

Department of 

Agriculture 

Marketing and 

Regulatory 

Programs 

Animal and 

Plant Health 

Inspection 

Service 
Table of Contents 

I. Purpose and Need.................................................................... 1 

A. Introduction........................................................................ 1 

B. Purpose and Need............................................................. 2 

II. Alternatives.............................................................................. 3 

A. No Action ........................................................................... 3 

B. Proposed Action ................................................................ 3 

III. Environmental Impacts........................................................... 6 

A. No Action ........................................................................... 6 

B. Proposed Action ................................................................ 7 

C. Cumulative Effects........................................................... 21 

IV. Other Environmental Considerations ................................... 22 

A. Endangered Species Act ................................................. 22 

B. Executive Orders ............................................................. 22 

V. Agencies, Organizations, and Individuals Consulted ............ 24 

VI. References........................................................................... 25 
1 

I. Purpose and Need 

A. Introduction 

Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) can cause 

economic damage to citrus in groves and nurseries by direct feeding. Both 

adults and nymphs feed on young foliage, depleting the sap and causing 

galling or curling of leaves. High populations feeding on a citrus shoot 

can kill the growing tip. 

ACP serves as a vector of an uncultured α-Proteobacteria, “Candidatus 

Liberobacter asiaticum,” which causes citrus greening disease (CG). CG, 

also known as huanglongbing or HLB, is considered to be one of the most 

serious citrus diseases in the world. CG attacks the vascular system of 

host plants. The bacteria present no threat to humans or animals. The 

bacteria are phloem-limited and cause yellow shoots, blotchy mottling and 

chlorosis, reduced foliage, and tip dieback of citrus plants. CG greatly 

reduces production, destroys the economic value of the fruit, and can kill 

trees. Once infected, there is no cure for a tree with CG. In areas of the 

world where CG is endemic, citrus trees decline and die within a few years 

and may never produce usable fruit. 

Within the United States, ACP is currently present in Alabama, California, 

Florida, Georgia, Guam, Hawaii, Louisiana, Mississippi, South Carolina, 

Puerto Rico, and Texas. CG was first detected in the United States in 

Miami-Dade County, Florida in 2005 and is only known to be present in 

Florida and Louisiana. 

The U.S. Department of Agriculture (USDA), Animal and Plant Health 

Inspection Service (APHIS) has undertaken measures to control the 

artificial spread1 of ACP and CG to noninfested areas of the United States 

since its introduction in 2005. APHIS has issued numerous Federal 

Orders2

 designating quarantined areas and has imposed moving 

restrictions, including the requirement of chemical treatments, when CG 

and ACP host plant and plant material are moved interstate from 

quarantined areas. 

APHIS, in cooperation with Texas A&M University – Kingsville Citrus 

Center (TAMU-KCC), is proposing to implement an ACP control research 

project in citrus groves and residential properties within Hidalgo County, 

Texas. The objective of the study is to demonstrate that ACP populations 

may be controlled in a coordinated fashion and at a regional level in 

 

1

 Humans moving CG or ACP host plant material have been responsible for the long-distance spread 

of CG and ACP; this is often referred to as "artificial" spread. 

2

 To view Federal Orders pertaining to controlling CG and ACP, go to 

http://www.aphis.usda.gov/plant_health/plant_pest_info/citrus_greening/regs.shtml. 
2 

managed and abandoned citrus groves and residential properties, to lower 

the potential risk posed by CG. This environmental assessment (EA) 

analyzes the potential environmental impacts of the proposed research 

project and its alternatives. 

B. Purpose and Need 

APHIS is responsible for taking actions to exclude, prevent, eradicate, 

and/or control plant pests, such as ACP, under the Plant Protection Act 

(7 United States Code (U.S.C.) 7701 et seq.). When scientific data is 

limited, APHIS may at times conduct research in an attempt to further 

develop pest control methods. 

 

The need for the proposed research project is to better understand how to 

manage ACP, the vector of CG, in a coordinated area-wide approach. The 

purpose of the project is to help protect the citrus industry, including the 

individual growers who comprise the base of that industry, by developing 

and providing sound ACP control strategies. The overall goal of the 

research would be to demonstrate that ACP populations may be 

satisfactorily controlled in a coordinated fashion at a regional level. This 

would include managed and abandoned citrus orchards, residential 

properties, and other non-commercial sites in order to lower the potential 

risk posed by CG. The research would attempt to: 

• Implement site-specific treatment regimes for ACP control in 

commercial citrus and refine monitoring methods for ACP 

populations and infestations before and after treatment; 

• In collaboration with homeowners, develop effective and 

acceptable control programs in residential citrus trees using 

approved bio-pesticides and registered chemicals; 

• Continue to test the efficacy of different insecticide application 

methods comprising aerial application (fixed winged aircraft) and 

ground application (standard high volume and reduced volume); 

• Monitor and document the effects of different ACP population 

control options on non-target arthropods, including beneficial and 

secondary pests species; 

• Develop grower and public education programs and promote 

cooperation and commitment from all stakeholders for dealing 

with ACP and the threat of CG in Texas. 

This EA will analyze the environmental impacts anticipated from 

implementation of the proposed research project. This EA has been 

prepared consistent with the National Environmental Policy Act of 1969 

(NEPA) (42 U.S.C. 4321, et seq.) and APHIS’ NEPA implementing 

procedures (7 CFR Part 372). APHIS provided a public comment period 

for this EA that ended on February 13, 2009. Comments were to be sent 
3 

to USDA/APHIS/PPQ Office, 320 North Main St. Suite 119, McAllen, 

Texas 78501 by February 12, 2009. No comments were received. 

II. Alternatives 

APHIS has considered two alternatives in response to the need to better 

understand effective ACP control strategies: (1) no action and (2) the 

proposed action. Each alternative is described briefly in this section, and 

the potential environmental impacts of each are considered in the 

following section. 

A. No Action 

Under the no action alternative, APHIS would not conduct the control 

research project. If the proposed research project is not conducted, APHIS 

may need to implement ACP management programs without the best 

research available. 

Hidalgo County is currently included in the October 1, 2008 Federal 

Order3

 for CG and ACP. Under this Federal Order, Hidalgo County is 

quarantined for ACP and therefore, any regulated articles4 must be 

chemically treated or irradiated in order for them to be moved interstate. 

However, this Federal Order applies to nurseries and not citrus groves and 

residential properties. Citrus groves are not required to treat against ACP. 

However, growers independently conduct control actions against other 

citrus pests using different pesticides. While some citrus growers in 

Hidalgo County are beginning to voluntarily treat against ACP, others 

continue to apply pesticides primarily against other citrus pests such as 

citrus rust mites. Some of their pesticide applications may control ACP 

for short periods of time, but others may have little effect on ACP 

numbers. The lack of a coordinated approach may result in greater 

pesticide use and sporadic control. 

B. Proposed Action 

Under the proposed action alternative, APHIS would conduct an ACP 

control research project to better understand effective ACP control 

strategies. APHIS could utilize the results of the project to develop and 

implement sound ACP management practices and to minimize the risk of 

introducing CG in citrus groves and residential properties in Texas as well 

as throughout the United States. 

 

3 To view the October 1, 2008 Federal Order, go to

http://www.aphis.usda.gov/plant_health/plant_pest_info/citrus_greening/downloads/pdf_files/federalor

der-10-1-08-san.pdf. 4

 As defined by the October 1, 2008 Federal Order, a regulated article includes all plants, budwood, 

cuttings, or other fresh or live plant parts, except seed and fruit, of a select group of ACP hosts. 
4 

APHIS, in cooperation with TAMU-KCC, would propose to citrus 

growers four treatment options to be applied on approximately 1,400 acres 

in Hidalgo, Texas. The 1,400 acres would lie within a 4,100 acre (13 

square mile area) treatment plot outlined in red in Figure 1 (see following 

page). 
1 

Figure 1. Proposed Treatment Plot in Hidalgo, Texas. The red outlined area indicates a 4,100 acre (13 square mile area) treatment plot. However, only approximately 

red outlined area would be treated under the proposed action. 
5 

The actual number of acres that would be under research would depend on 

the treatment regime tested, funding available, and grower cooperation. 

Other details of the research are as follows: 

1. Monitoring for ACP populations: Monitoring would be 

conducted both within the project-managed area and outside the 

managed area. A sticky trap grid would be set up within the 

project-managed area and extend into the surrounding region. 

Additional direct sampling observations would be made in the 

orchards. Flush5 data would also be collected on the citrus trees. 

2. Chemical treatments: Treatments would take place within citrus 

groves as well as residential properties. The implementation of 

any treatment program at a given participating orchard or residence 

would depend on the grower’s or homeowner’s choice of 

participating or not, and choice of treatment options. Several 

treatment options are proposed to allow flexibility and 

compatibility with ongoing grower pest management programs. 

Treatments would be applied via different application methods as 

noted in the tables below. Foliar applications in groves could be 

made by air or ground applications. Foliar applications on 

residential properties would be made via hand-held sprayers. All 

soil applications would be made below the surface of the soil. 

a. Treatment Options for Citrus Grove Growers: 

Option 

# 

Chemical 

Treatments 

Application Method Application 

Date 

1) Fenpropathrin Aerial or ground foliar application mid February 

2) Aldicarb Soil incorporation (burial) application March 

3) Fenpropathrin Aerial or ground foliar application April 

4) Imidacloprid Aerial or ground foliar application June 

1 

5) Chlorpyrifos Aerial or ground foliar application September 

1) Fenpropathrin Aerial or ground foliar application mid February 

2) Imidacloprid Soil injection application March to April 

3) Zeta-cypermethrin Aerial or ground foliar application July 

2 

4) Chlorpyrifos Aerial or ground foliar application September 

1) Fenpropathrin Aerial or ground foliar application mid February 

2) Imidacloprid Aerial or ground foliar application March to April 

3) Imidacloprid Soil injection application June 

3 

4) Chlorpyrifos Aerial or ground foliar application September 

1) Pyrethrin Aerial or ground foliar application mid February 

2) Kaolin clay Aerial or ground foliar application March-April 

3) Citrus oil Aerial or ground foliar application June 

4 

4) Neem oil Aerial or ground foliar application September 

 

5

 Flush generally refers to that time early in the annual growing cycle when plants rapidly produce 

large amounts of new growth. Citrus trees in the Lower Rio Grand region flush early in the spring 

during bloom and typically have three or more additional periods of flush throughout the growing 

season based on irrigation and rain events. 
6 

Based on APHIS’ proposed study, citrus oil, kaolin, pyrethrin, and 

neem oil would be used to treat no more than 100 acres within 

established citrus groves. Aldicarb and zeta-cypermethrin would 

be used to treat no more then 650 acres within established citrus 

groves. Chlorpyrifos, fenpropathrin, imidacloprid would be used 

to treat no more than 1,300 acres within established citrus groves. 

b. Treatment Options for Residential Properties: 

Option 

# 

Chemical Treatments Application Method 

1) Pyrethrin, citrus oil, or neem oil Ground foliar application via hand-held sprayer 

2) Imidacloprid Soil injection and tablet 

1 

3) Pyrethrin, citrus oil, or neem oil Ground foliar application via hand-held sprayer 

1) Kaolin clay Ground foliar application via hand-held sprayer 

2) Citrus oil Ground foliar application via hand-held sprayer 

2 

3) Pyrethrin Ground foliar application via hand-held sprayer 

3. Monitoring non-target species: The effects of different ACP 

population control options on non-target arthropods, including 

beneficial and pest species, would be monitored using both yellow 

sticky cards and direct visual observations of citrus plants. 

III. Environmental Impacts 

The potential environmental effects from each of the alternatives being 

considered are discussed below. 

A. No Action 

Under the no action alternative, APHIS would not conduct the control 

research project. If the proposed research project is not conducted, APHIS 

may need to implement ACP management programs without the best 

research available. Control of ACP and CG may be compromised under 

this alternative, thereby risking damage to citrus groves. 

While some growers in Hidalgo County are beginning to treat specifically 

against ACP, others continue to apply pesticides primarily against other 

citrus pests such as citrus rust mites. Some of their pesticide applications 

may control ACP, but others may have little effect on ACP numbers. This 

may result in uncoordinated applications of pesticides that may have 

limited impact on ACP pest populations, possibly increasing the number 

of applications by individual growers to manage ACP. 
7 

B. Proposed Action 

Under the proposed action alternative, APHIS would conduct an ACP 

control research project to better understand effective ACP control 

strategies. APHIS could utilize the results to implement sound ACP 

management practices and minimize the risk of introducing CG in citrus 

groves and residential properties in Texas as well as throughout the United 

States. 

The aspects of the project that include routine measures, i.e., monitoring, 

inspections, surveys, and sampling, are program activities that pose 

negligible environmental effects and will not be discussed further. The 

primary action in this proposed control research project that could be 

associated with any potentially noteworthy environmental impacts is the 

use of chemical treatments. The potential environmental impacts, 

including impacts to humans, from the use of chemical treatments are 

discussed below. 

Due to the flexibility in treatment options, it is conceivable that in some 

cases there would not be a net increase in the number of chemical 

treatments used on any given citrus tree. There may actually be fewer 

chemical treatments because of the coordination of treatments between 

growers and combined treatments for multiple pests. Under the research 

program, growers may replace a pesticide used primarily to kill a pest 

such as the citrus rust mite with another pesticide effective at killing not 

only the citrus rust mite but also ACP. 

 

The optional chemical treatments are listed below followed by a summary 

of effects to human health, non-target organisms, and overall 

environmental quality.

(1) Aldicarb (citrus grove use only)

(a) Human Health 

Aldicarb is a N-methyl carbamate insecticide with a primary mode of 

action that acts through the inhibition of cholinesterase. Aldicarb is 

considered highly toxic to mammals through oral, inhalation, and dermal 

routes. Acute oral median lethality values are approximately 1 mg/kg for 

the technical material while the formulated material has a reported median 

lethality value of 8.4 mg/kg. Several subchronic and chronic studies 

assessing a variety of endpoints have been conducted with aldicarb and the 

most sensitive endpoint in most of those studies is a reduction in 

cholinesterase levels (EPA, 2006). Aldicarb is not considered to be a 

teratogen, mutagen or a carcinogen (EPA, 2006). 
8 

Significant exposure and risk are not expected for the general public 

because aldicarb would be applied as a granule into furrows where it must 

be applied at a minimum depth of 2 inches below the soil line and then 

covered with soil to reduce exposure to non-target organisms and 

maximize performance. However, there is the potential for exposure to 

workers and applicators. The area of treatment in this program would be 

no more than 650 acres contained within a larger citrus grove. Exposure 

to workers and applicators would be minimized through the use of 

personal protective equipment and adherence to all label language. All 

applications would be made using ground equipment, and aldicarb would 

be applied as a granule, thereby minimizing applicator exposure as well as 

off-site transport from drift or runoff. Although aldicarb does exhibit 

environmental fate properties that could pose a risk to drinking water, 

label language prohibits applications at a minimum distance of 50 feet 

from any drinking water well. Moreover, drinking water concerns are 

minimized by the absence of a high water table or drinking water 

reservoirs near the proposed application sites and by the lack of soils 

conducive for lateral or vertical transport of contaminated water. 

(b) Non-target Organisms 

Aldicarb is considered to be highly toxic to most non-target organisms. It 

is considered very highly toxic to birds with median lethal oral doses 

ranging from 0.82 mg/kg to approximately 5 mg/kg (EPA, 2009; EPA, 

2005a). Aldicarb is also considered highly toxic to terrestrial invertebrates 

such as pollinators and earthworms (EPA, 2005a). Toxicity to aquatic 

organisms is more variable, depending on the test species. Aldicarb is 

moderately to highly toxic to aquatic invertebrates based on median 

lethality values that range from the low part per billion to low part per 

million range. Aldicarb is considered highly toxic to fish based on 

available acute toxicity data for several surrogate test species that report 

median lethality values in the low to mid part per billion range. 

Exposure and risk to non-target organisms is expected to be minimal, 

based on the use pattern for aldicarb and the lack of sensitive natural 

aquatic resources near the site of application. Direct risk to mammals and 

birds would be minimal, based on the lack of exposure expected when the 

label directions are followed. Aldicarb would be applied as a granule into 

furrows where it must be applied at a minimum depth of 2 inches below 

the soil line and then covered with soil to reduce exposure to non-target 

organisms and maximize performance. The lack of granules on the 

ground surface would reduce the potential for primary or secondary risk to 

terrestrial vertebrates. Some soil invertebrates and those that feed on 

treated trees may be impacted by the treatment of aldicarb; however, the 

risk would be restricted to a small area within the citrus grove. 
9 

Exposure and risk to aquatic resources would also be minimized by the 

method of application which eliminates the possibility of drift and greatly 

reduces the potential for runoff. Natural aquatic habitats do not occur in 

proximity to the proposed treatment site which further reduces any risk 

from subsurface flow and runoff of aldicarb. Some man-made canals and 

ponds exist in the area; however, the method of application and adherence 

to the label would reduce potential exposure from runoff. 

(c) Environmental Quality 

The use of aldicarb in this program is not expected to cause significant 

negative impacts to soil, water, or air. Aldicarb use would be limited to an 

area of no greater than 650 acres within established citrus orchards. Based 

on the method of application and the low propensity for volatilization, 

aldicarb is not expected to impact air quality. There are concerns about 

aldicarb residues in water based on environmental fate characteristics; 

however, impacts to water are not expected, based on precautionary label 

language and the lack of proximity of drinking surface or groundwater to 

the proposed treatment area. Impacts to soil would be limited to those 

areas immediately adjacent to the areas where application occurs around 

an individual tree. 

(2) Chlorpyrifos (citrus grove use only)

(a) Human Health 

Chlorpyrifos is an organophosphate insecticide that can cause neurotoxic 

effects. The toxicity of chlorpyrifos occurs primarily through the 

inhibition of acetylcholinesterase enzyme activity which permits the 

transmission of nerve impulses across the nerve synapse. Signs and 

symptoms of low doses include localized effects (such as nosebleeds, 

blurred vision, and bronchial constriction) and systemic effects (such as 

nausea, sweating, dizziness, and muscular weakness). At higher doses the 

signs and symptoms include irregular heartbeat, elevated blood pressure, 

cramps, and convulsions. Acute oral toxicity is moderate, based on 

median lethality values ranging from 60 to 1000 mg/kg depending on the 

test species. Dermal toxicity is considered low, and the formulated 

material can cause moderate eye and skin irritation. Chlorpyrifos is not 

considered mutagenic, teratogenic, or carcinogenic by the U.S. 

Environmental Protection Agency (EPA) (USDA, APHIS, 2005). 

The application of this pesticide would be limited to one application by 

either ground or air in areas that are established citrus groves. The 

potential area of application within groves would be no greater than 

1,300 acres since it is planned for use in three of the four citrus grove 

options. The only individuals that could potentially be affected by the use 

of this insecticide are the citrus grove workers and applicators. Adherence 
10 

to label language regarding the application of chlorpyrifos, including 

personal protective equipment and safety precautions and standard 

program operating procedures, would minimize exposure and risk to 

program workers (USDA, APHIS, 2005). 

(b) Non-target Organisms 

Chlorpyrifos is considered to be moderately to highly toxic to birds, 

depending on the test species (EPA, 2009; USDA, APHIS, 2005). 

Symptoms of nonfatal exposure to birds include cholinesterase depression 

(ChE), weight loss, reduced egg production, and reduced hatchling 

survival. Chlorpyrifos applications would only occur within established 

citrus groves as a one time application to no more than 1,300 acres by 

either ground or air during late summer. Direct risk to birds and mammals 

in the area of treatment could occur; however, these animals are not 

expected to be present during the time of application due to disturbance 

from application equipment moving through the citrus grove. Terrestrial 

vertebrates outside the spray block would have reduced exposure based on 

the label requirements that would minimize off-site transport of 

chlorpyrifos. Indirect risk to terrestrial vertebrates through the loss of 

insect prey would be minimized by colonization of the area by other 

invertebrates after the individual treatment and the expanded foraging 

capability of mammals and birds into non-treated areas. Impacts to 

terrestrial invertebrates, such as earthworms and worker honey bees, are 

expected; nevertheless, this effect would be restricted to areas within the 

citrus grove, and invertebrates from outside the treatment area would 

repopulate areas after treatment. In addition, precautionary language 

prohibiting applications to blooming plants when bees are actively 

foraging would further reduce impacts to pollinators. 

Chlorpyrifos is highly toxic to fish and aquatic invertebrates, with acute 

median lethality values ranging from the low parts per trillion to low part 

per billion range depending on the test species (EPA, 2009; USDA, 

APHIS, 2005). Exposure and risk to aquatic resources in man-made 

canals and farm ponds in the area would be minimized by following 

precautionary label language to reduce drift and by applying buffers of 

25 feet for ground applications and 150 feet for aerial applications from all 

aquatic resources.

(c) Environmental Quality 

Potential effects of chlorpyrifos on air, soil, or water quality would be 

restricted to the area of application. Chlorpyrifos can persist in soil and 

water for several months under certain conditions; however, the 

persistence is generally only for a month or less. This is dependent on the 

organic content of the soil. Chlorpyrifos degrades quickly in the presence 

of light, with a half life of approximately 2.7 hours, and in water will bind 
11 

readily with sediment with aqueous half lives ranging from 7 to 28 days. 

Chlorpyrifos can volatilize into the atmosphere; however, its persistence is 

expected to be short, with a half life of only a few hours due to photolytic 

sensitivity (USDA, APHIS, 2005). Chlorpyrifos can impact air quality 

through drift from ground or aerial applications. These impacts would be 

restricted to areas within established citrus groves with off-site transport 

reduced by strict adherence to all precautionary label language regarding 

the minimization of drift. 

(3) Citrus Oil 

(a) Human Health 

Citrus oil is a biological insecticide derived from the extraction of oils 

from citrus that can be used to control certain insect pests. These oils are a 

proprietary mixture of different materials, with limonene being one of the 

components with insecticidal activity. Constituents of citrus oil have been 

shown to have low mammalian toxicity (EPA 1994). Prolonged inhalation 

of mist or vapors of the formulated material can cause adverse effects, and 

contact with the eye can cause substantial irritation. 

Citrus oil use in this program would be as a foliar application in citrus 

groves or to host plants on residential properties. Applications in citrus 

groves can occur via ground or air to no more than 100 acres, while 

residential applications would be made using hand-held sprayers. In citrus 

groves exposure would be restricted to workers and applicators. Based on 

available toxicity data and the requirements for personal protective 

equipment, human health risk is expected to be minimal. Significant 

exposure and risk to residents are also not expected, based on the method 

of application and proper notification to residents whose property may be 

treated. 

 (b) Non-target Organisms 

Environmental toxicology data for citrus oils is limited; however, data for 

some constituents contained within these types of materials, such as 

limonene, demonstrate that acute and subacute toxicity to birds is 

extremely low, with values exceeding the highest test concentration. 

Toxicity to terrestrial invertebrates such as honey bees is unknown. 

Aquatic toxicity is low, with median lethality values in the low part per 

million range for invertebrates and fish based on limited data (Kassir, et al. 

1989; EPA, 1994). 

The low toxicity to terrestrial vertebrates suggests minimal direct risk to 

wild mammals and birds. Indirect risk through the loss of insect prey to 

this group of organisms is unknown based on the lack of data for 

terrestrial invertebrates, but is expected to be minimal since only one 
12 

application is being made to an area no greater than 100 acres within 

established citrus groves and some host plants on residential properties. 

Any impacts to terrestrial invertebrates would be localized and smaller 

than foraging areas for most terrestrial vertebrates. In addition, citrus oils 

are not considered broad spectrum insecticides; therefore, not all 

invertebrates would be impacted. Exposure and risk to aquatic resources 

are expected to be minimal. Natural aquatic habitats do not occur in 

proximity to the areas of treatments; and even under worse case exposure, 

scenarios risk to aquatic resources located in ponds and canals is expected 

to be minimal. Citrus oil applications are not expected to impact surface 

drinking water supplies or groundwater since these sources do not occur in 

proximity to the proposed application, and citrus oil would not be 

considered a mobile pesticide. 

(c) Environmental Quality 

Citrus oil impacts to soil, water, and air quality are expected to be 

negligible. It would only be applied once within a season to an area no 

greater than 100 acres in size and to host plants on some residential 

properties. All treatments would be made so as to minimize off-site 

transport, thereby minimizing impacts to water quality. Citrus oil can 

occur in the atmosphere as drift from ground and aerial applications; 

however, this impact would be short in duration and minimized by using 

larger droplet sizes, where applicable, and by using drift best management 

practices that enhance efficacy and reduce offsite transport. 

(4) Fenpropathrin (citrus grove use only)

(a) Human Health 

Fenpropathrin is a synthetic pyrethroid insecticide which affects the 

nervous system. It is a moderate skin and eye irritant. Signs and 

symptoms can include muscle contractions, tremors, ataxia, and nerve 

paralysis at moderate to high levels of exposure. Fenpropathrin is not 

considered carcinogenic by EPA (USDA, APHIS, 2005). 

The application of this pesticide would be limited to one ground or aerial 

treatment to no more than 1,300 acres within an established citrus grove. 

Potential pesticide exposures would be limited to citrus grove workers and 

the occupational workers who apply the pesticide. Personal protective 

equipment and safety precautions required by the label and standard 

program operating procedures are designed to ensure that no adverse 

effects to applicators are expected (USDA, APHIS, 2005). 
13 

(b) Non-target Organisms 

The program use of fenpropathrin is unlikely to impact most non-target 

wildlife. The toxicity of fenpropathrin is moderate to mammals and has a 

slight oral toxicity to birds. Direct risk to terrestrial vertebrates is not 

expected due to the moderate toxicity of fenpropathrin and expected low 

exposure from ground or aerial applications. Terrestrial invertebrates 

would be impacted in areas of treatment; however, these effects would be 

restricted to treated areas within the citrus grove and would be temporary 

due to recolonization from untreated areas (USDA, APHIS, 2005). 

Indirect risk to terrestrial vertebrates through the loss of insect prey would 

be minimized by recolonization of the area by other invertebrates after the 

individual treatment and the expanded foraging capability of mammals 

and birds into non-treated areas. Impacts to honey bees would be reduced 

by adherence to precautionary language present on the label. 

Fenpropathrin is highly toxic to aquatic organisms, with median lethality 

values ranging from the low part per trillion to low part per billion range 

for fish and aquatic invertebrates. Risk to aquatic resources in natural 

aquatic habitats is not expected due to the lack of these resources being 

present near the area of application. There are farm ponds and man-made 

canals in proximity to the proposed area of treatment; however, exposure 

and risk to these habitats would be minimized by following precautionary 

label language to reduce drift and label requirements for application 

buffers of 25 feet for ground applications and 250 feet for aerial 

applications adjacent to aquatic water bodies. 

(c) Environmental Quality 

Impacts to air, water, and soil from the proposed fenpropathrin 

applications are expected to be minimal, based on its use pattern and 

environmental fate properties. Fenpropathrin is considered persistent in 

water at environmentally relevant pH values; however, it will dissipate 

rapidly due to its strong binding affinity to soil and sediment. Photolytic 

degradation in soil is more rapid when compared to water, with reported 

half lives in water greater than a year and 14 days in soil. Potential 

mobility is low, based on low water solubility and a high binding affinity 

for soil, which reduces the potential for runoff. Residues on treated 

vegetation are also of short persistence (USDA, APHIS, 2005). 

(5) Imidacloprid (citrus grove and residential use)

(a) Human Health 

Imidacloprid belongs to a class of insecticides called neonicitinoids, which 

act by binding directly to the acetylcholine binding receptor. Imidacloprid 

is a chemical that has systemic transport qualities in plants, which make it 
14 

efficacious against psyllids and other sucking insects when it is applied as 

a soil injection or tablet treatment to soil or as a foliar spray. 

The acute oral median lethal toxicity of imidacloprid is considered to be 

moderate to mammals. Inhalation and acute dermal toxicity are 

considered to be low. The formulation of imidacloprid to be used in the 

program is of comparable or lower toxicity than the active ingredient. The 

program applications are not expected to pose dermal irritation or 

sensitization, and only mild eye irritation. Primary metabolites and 

degradation products of imidacloprid are of lower toxicity than the parent 

compound, based on available data. Imidacloprid is rapidly excreted by 

mammals. Based upon several in vitro and in vivo studies, imidacloprid is 

not considered to be mutagenic or genotoxic (USDA, APHIS, 2008). The 

EPA has classified imidacloprid in “Group E” in regard to carcinogenic 

potential. This indicates that the submitted studies provide evidence of 

noncarcinogenicity to humans. 

In this program, imidacloprid is applied as a soil injection or tablet below 

the soil surface, or as a foliar treatment. The total amount of acreage 

potentially treated would be no greater than approximately 1,300 acres 

since it would be used in three of the four application scenarios in citrus 

groves as well as one of the options in treating dooryard citrus. Exposure 

of applicators via inhalation, dermal contact, and oral intake of the active 

ingredient in these formulations would be minimal due to the method of 

application, personal protective equipment, and the environmental fate of 

imidacloprid. This is especially the case for the tablet and soil injection 

applications. Potential acute and chronic exposure scenarios indicate 

minimal risk to workers as well as to residents where soil injection or 

tablet applications would occur (USDA, APHIS, 2008). Foliar 

applications would also result in negligible risk to workers and applicators 

based on the toxicity of imidacloprid and the use of appropriate protective 

equipment. In cases where dooryard citrus applications are made, proper 

notification would be given to those residents to further reduce exposure. 

(b) Non-target Organisms 

Imidacloprid is considered to be toxic to birds, with acute oral median 

lethal toxicity values ranging from 41 to 152 mg/kg. The limited 

applications to specific citrus host plants result in potential effects to 

invertebrates that are likely to be localized. Concerns have been raised 

about potential lethal and sublethal effects to honey bees and other 

pollinators. Median lethal toxicity values of imidacloprid have been based 

upon oral or contact exposure. Laboratory and field studies of honey bees 

indicate a lack of adverse effects at test concentrations comparable to 

realistic exposure scenarios, and adverse health impacts to hives only with 

greater exposures (USDA, APHIS, 2008). 
15 

Exposure to wild mammals and birds from applications of imidacloprid 

and associated residues is not expected to occur at levels that could result 

in significant risk (USDA, APHIS, 2008). The terrestrial insects that feed 

upon vegetation of those host plants that have been treated with tablet, 

foliar, or soil injection applications are likely to be impacted, but the 

effects would be restricted to the areas of treatment. Any predatory or 

parasitic insects that depend upon these phytophagous insects would also 

be affected due to loss of prey. Mammals and birds that are insectivorous 

would not depend upon the affected insects and would expand their 

foraging range to ensure adequate consumption. Risk to honey bees and 

pollinators is expected to be minimal, based upon the expected residues 

and lack of observed impact from acute and chronic toxicity studies of 

such applications. 

Aquatic vertebrates and invertebrates can be exposed through runoff or 

drift from the site of application. Significant drift is not expected from the 

soil injection and tablet applications, but some drift could occur with foliar 

applications in citrus groves. This is not expected to result in toxic effects 

to aquatic vertebrates, but could pose some risks to aquatic invertebrates 

(USDA, APHIS, 2008). Exposure and risk to aquatic invertebrates would 

be minimized due to the lack of natural aquatic habitats near the area of 

treatment. Exposure and risk to aquatic resources in man-made canals and 

farm ponds in the area would be minimized by following precautionary 

label language to reduce drift and application buffers of 25 feet for ground 

applications and 150 feet for aerial applications from all aquatic resources.

(c) Environmental Quality 

The half life of imidacloprid in soil under field conditions ranges from 7 to 

107 days. Imidacloprid does not adsorb strongly to soil particles. 

Imidacloprid is soluble in water and has a half life under natural light of 

less than 5 hours in water. Imidacloprid is not expected to volatilize to the 

atmosphere to any measurable extent. The half life of imidacloprid on 

vegetation ranges from 1.17 to 9.8 days, but the tablet and injection do not 

involve foliar exposure other than some residues splashed on ground 

covering plants (USDA, APHIS, 2008). Imidacloprid is readily taken up 

by plants and translocated; however, program treatments are not expected 

to result in any bioaccumulation hazards (USDA, APHIS, 2005). 

(6) Kaolin Clay 

(a) Human Health 

Kaolin is a naturally occurring aluminosilicate material that has a nontoxic mode of action by acting as a repellant or by providing a protective 

barrier from insects and disease. In addition to its use for insect and 

disease control, kaolin is widely used in health products and toiletries and 
16 

as an indirect food additive (EPA, 2000). The formulation proposed for 

use in this program is OMRI (Organic Materials Review Institute) 

certified. 

Based on available toxicity data, kaolin has low acute toxicity via oral, 

dermal, and inhalation routes. Kaolin is a minor eye irritant and is not 

considered a dermal irritant. The formulated product proposed for use in 

this program, which is a dust, may cause irritation to the throat, eye, and 

skin to workers; however, adherence to the label and recommended 

personal protective equipment would reduce exposure. Exposure to 

workers and applicators to the formulated material would be substantially 

reduced once the product is mixed with water per label directions. 

Applications in citrus groves would be limited to one application to an 

area no greater than 100 acres. A ground treatment for host plants may 

occur as part of the dooryard citrus application; however, risk to any 

residents in the area is expected to be minimal based on the low toxicity of 

kaolin clay and expected low exposure. Applications to properties where 

residents may be present would only occur after proper notification so that 

residents can take appropriate precautionary steps. 

 (b) Non-target Organisms 

Available toxicity data for kaolin as well as other clay materials suggest 

low toxicity to non-target terrestrial vertebrates. Toxicity to terrestrial 

invertebrates, such as pollinators, is also considered low, based on 

available data where acute median lethality values were greater than the 

highest concentration tested (EPA, 2000). Available toxicity data for 

related clay materials to non-target aquatic organisms demonstrate very 

low toxicity to aquatic invertebrates and vertebrates, with toxicity values 

typically above 100 parts per million (WHO, 2005). Exposure and risk to 

non-target organisms are expected to be minimal, based on the low 

toxicity of kaolin and the relatively small areas of treatment within citrus 

groves and residential properties. 

(c) Environmental Quality 

Kaolin use in this program is not expected to cause adverse impacts to 

soil, water, or air. Its use would be limited to a small area within citrus 

groves or to host plants on residential properties, and is not expected to 

have adverse impacts on soil or water. In addition, significant 

volatilization or drift is not expected into the atmosphere, based on the 

physical properties of kaolin once it is mixed and applied to the foliage of 

host plants. 
17 

(7) Neem Oil 

(a) Human Health 

Neem oil is an extract from the neem plant that contains azadirachtin, 

which has insecticidal properties by disrupting insect molting by acting as 

an ecdysone antagonist. The formulated material has very low acute oral, 

dermal, and inhalation toxicity, with all median lethality values greater 

than the highest concentration tested. It is considered a mild skin irritant 

but is not an eye irritant or a skin sensitizer. Azadirachtin is not 

considered mutagenic or carcinogenic according to the data provided on 

the material safety data sheet. The formulation proposed for use in this 

program is OMRI (Organic Materials Review Institute) certified. 

Exposure and risk to humans from neem applications are expected to be 

minimal. An aerial or ground application would occur within established 

citrus groves to an area no greater than 100 acres, where exposure would 

be greatest for workers and applicators. The low toxicity and adherence to 

label recommendations would minimize risk to this segment of the 

population. A ground treatment may occur as part of the dooryard citrus 

application; however, risk to any residents in the area is expected to be 

minimal, based on the low toxicity of neem oil and the expected low 

exposure. Applications to properties where residents may be present 

would only occur after proper notification. Neem oil is not expected to be 

a threat to surface drinking water supplies or groundwater based on its 

chemical properties and the lack of these sources present in proximity to 

the proposed treatment area. 

 (b) Non-target Organisms 

Azadirachtin is considered practically non-toxic to birds, with reported 

median lethality values greater than the highest test concentration. It is 

considered moderately toxic to some terrestrial invertebrates, including 

honey bees, and is considered toxic to aquatic organisms, with median 

lethality toxicity values ranging from the low part per billion to low part 

per million range (EPA, 2009). 

Significant exposure and risk to terrestrial vertebrates are not expected 

from the use of azadirachtin due to its low toxicity and limited application 

to small areas within established citrus groves. Applications in citrus 

groves can occur by air or ground, but would be limited to one application 

to a maximum area of 100 acres. Some residential applications may also 

occur via ground hand-held spray equipment. Indirect risk to vertebrates 

that use invertebrate prey as a food source would be low, since 

azadirachtin is selective in its impacts to terrestrial invertebrates and the 

area of treatment is small relative to the foraging area for most vertebrates. 
18 

Exposure and risk to aquatic resources are also expected to be minimal. 

Application rates and the lack of natural aquatic habitats in proximity to 

the area of treatment would minimize risk to aquatic resources. There are 

man-made canals and farm ponds in proximity to the treatment block; 

however, the low application rates and adherence to the precautionary 

statements on the label would minimize risk and exposure to aquatic 

resources. 

(c) Environmental Quality 

Azadirachtin use in this program is not expected to cause adverse impacts 

to soil, water, or air. Its use would be limited to a small area within citrus 

groves or to host plants on residential properties and is not expected to 

have adverse impacts to soil or water. Degradation in soil appears to be 

mediated by microbial organism resulting in half lives of approximately 

20 days at 25°C (Stark and Walter, 1995). Persistence in water varies, with 

reported dissipation half lives as short as a day up to 30 days (Thompson 

et al., 2004). Azadirachtin is not expected to sorb strongly to soil and is 

very susceptible to photolysis with half lives less than one hour (Johnson 

and Dureja, 2002). Azadirachtin is not expected to volatilize into the 

atmosphere and would only occur as drift from ground or aerial 

applications. Photolytic instability and the use pattern in this program 

would minimize any potential off-site impacts to air quality. 

(8) Pyrethrin

(a) Human Health 

Pyrethrins are naturally derived extracts from certain species of 

chrysanthemum plants that have insecticidal properties. The mode of 

toxic action occurs through effects on the sodium channels to stimulate 

nerves to produce repetitive discharges. Muscle contractions are sustained 

until a block of the contractions occurs. Nerve paralysis can occur at high 

levels of exposure (Walker and Keith, 1992). Pyrethrins have certain 

properties that serve to both intoxicate and repel certain insects. Their 

control activity occurs through contact exposure, so thorough coverage of 

the host plants is important to successful control of ACP. 

The acute oral toxicity of pyrethrin to mammals is considered to be low to 

moderate. Acute dermal and inhalation toxicity are also low. The 

formulation of pyrethrin to be used in the program has comparable acute 

toxicity to the active ingredient. This formulation poses slight dermal and 

eye irritation. The primary metabolites and degradation products of 

pyrethrin are considered to be of lower toxicity than the parent compound 

(EPA, 2005b). Pyrethrin is not considered mutagenic, teratogenic, or 

carcinogenic, based on available toxicity data (EPA, 2005b) 
19 

Pyrethrin is applied one time as an aerial or ground foliar treatment in 

citrus groves or by ground on residential properties. Worker exposure is 

minimized through the use of protective clothing and adherence to safety 

precautions. The potential exposure to applicators was determined to be 

from one to three orders of magnitude lower than the toxicity reference 

dose, suggesting minimal risk to workers (USDA, 2008). Based on the 

available toxicity data, residential exposure and risk would be minimal 

through notification of residents at the time of application so as to 

minimize exposure. Ingestion of contaminated drinking water and treated 

citrus fruit in residential applications were exposure scenarios analyzed for 

the use of pyrethrin. All potential risks for children and adults were 

determined to be negligible (USDA, 2008). 

(b) Non-target Organisms 

Pyrethrins have low toxicity to terrestrial vertebrates such as birds and 

mammals, suggesting low direct risk. Indirect risk to terrestrial 

vertebrates through the loss of terrestrial invertebrate prey is not expected 

due to the limited areas of application relative to the foraging range for 

most mammals and birds. Impacts to terrestrial invertebrates, such as 

pollinators, would be expected where pyrethrin applications are made; 

however, these impacts would be minimized by selective treatment of 

citrus and adherence to all precautionary label language. 

Pyrethrins are highly toxic to aquatic invertebrates and vertebrates. Acute 

median lethality values are in the low ppb range based on available data. 

Exposure in natural aquatic habitats is not expected due to the lack of 

these habitats being present in the area of treatment. There are man-made 

canals and farm ponds in proximity to the treatment block; however, 

adherence to precautionary label language would reduce exposure and risk 

to aquatic resources in these habitats. 

(c) Environmental Quality 

The use of pyrethrins in this program is not expected to have adverse 

impacts to soil, water, or air, due to their limited use and environmental 

fate profile. Half lives in soil and water are very short, thereby reducing 

the time for any potential impacts to soil and water quality. The half life of 

pyrethrin in soil ranges from 3.2 to 10.5 days. Pyrethrins bind tightly to 

soil particles, reducing the bioavailability in terrestrial and aquatic 

systems. Pyrethrins are light sensitive and have a photolysis half life less 

than 4 hours. Pyrethrins have low water solubility and short half lives of 

14 to 17 hours in alkaline water. In addition, no sensitive, naturally 

occurring, aquatic habitats are in proximity to the application sites. 

Impacts to air quality are also not expected, based on the chemical 

characteristics of pyrethrin that suggest low volatility. Pyrethrin would 

occur in the atmosphere as drift from ground and aerial applications; 
20 

however, adherence to the label would minimize the potential for off-site 

drift. 

(9) Zeta-cypermethrin (citrus grove use only) 

(a) Human Health 

Zeta-cypermethrin is a synthetic pyrethroid insecticide that is used to 

control a variety of insect pests in agricultural and structural/residential 

uses. The active ingredient is a combination of eight isomers, with four of 

the most insecticidally active occurring at higher concentrations compared 

to cypermethrin. Formulated zeta-cypermethrin is moderately toxic via 

oral and inhalation routes of exposure to mammals but is considered to 

have low dermal toxicity. The formulated material is moderately irritating 

to the eye and skin but is not considered a skin sensitizer. Zetacypermethrin is not considered mutagenic or teratogenic but is considered 

a possible carcinogen, based on results from a chronic mouse study where 

benign alveologenic neoplasms were observed at the highest dose level. 

These levels are well above those expected in this program. Similar 

effects were not observed in other test species in chronic studies (EPA, 

2005). 

Exposure of the general public to zeta-cypermethrin during applications in 

this program is not expected since applications would occur within 

established citrus groves. The potential for exposure is greatest for 

workers and applicators during the time of application. The one-time 

application would be restricted to an area no greater than 650 acres. 

Adherence to label language regarding personal protective equipment and 

other label requirements would minimize exposure to workers and 

applicators and provide adequate margins of safety. Applications are not 

expected to impact drinking water supplies due to the absence of surface 

drinking water or groundwater supplies in proximity to the area of 

application. In addition, zeta-cypermethrin has very low solubility and a 

high binding affinity for soil, which indicates a low probability of vertical 

or lateral transport into groundwater.

(b) Non-target Organisms 

Zeta-cypermethrin has low acute and chronic avian toxicity, with reported 

acute median lethal doses and chronic no observable effect concentrations 

greater than the highest test concentration (EPA, 2005). Toxicity is high 

to most terrestrial invertebrates, including honey bees, with label 

statements regarding minimizing exposure in areas where bees are actively 

foraging. Zeta-cypermethrin is considered highly toxic to aquatic 

invertebrates and vertebrates, with reported median lethality values in the 

low part per trillion to low part per billion range depending on the test 
21 

species. However, fish were slightly less sensitive when compared to 

aquatic invertebrates (Solomon et al., 2001; EPA, 2005; EPA, 2009). 

Risk to terrestrial vertebrates is expected to be minimal, based on the low 

toxicity of zeta-cypermethrin to birds and mammals and its limited use in 

the program, where no more than 650 acres would be treated once within a 

citrus grove. Indirect risk to birds and animals that depend on insect prey 

is expected to be minimal and localized, based on the small area of 

treatment. Terrestrial invertebrates would be impacted in the area of 

treatment; however, recolonization of non-target terrestrial invertebrates 

should occur quickly due to the size of the treatment area. The risk to 

aquatic resources would be limited to man-made canals or ponds located 

in the treatment area. No naturally occurring aquatic habitats are present 

in the proposed area of treatment, and the risk to aquatic resources in 

canals and ponds would be reduced by the use of aerial and ground 

application buffers, drift mitigation language, and vegetative filter strips – 

all of which are stated on the label. 

(c) Environmental Quality 

Zeta- cypermethrin is not expected to cause adverse impacts to soil, water, 

or air quality, based on its limited use in this program, mitigation measures 

proposed on the label, and environmental fate characteristics. Its use 

would be limited to one application on no more than 650 acres within an 

established citrus orchard. Therefore, any potential impacts would be 

localized. Zeta-cypermethrin breaks down in soil under aerobic and 

anaerobic conditions, with half lives less than 65 days. Zeta-cypermethrin 

is not expected to impact water quality due to the absence of sensitive 

aquatic habitats or drinking water supplies located in proximity to the area 

of treatment. In addition, the label requires vegetative buffer strips and 

application buffers from aquatic habitats, reducing the potential for 

exposure from ground or aerial applications. Zeta-cypermerthrin has very 

low water solubility and a high binding affinity to soil and sediment, 

further reducing the potential for runoff into any drinking water supply or 

sensitive aquatic habitat. Physical and chemical characteristics for zetacypermethrin preclude significant volatilization into the atmosphere. 

Zeta-cypermethrin may be present as drift in the air, following ground and 

aerial applications; however, strict adherence to the label, including the 

spray drift precautionary language, as well as the small area of treatment 

would minimize off-site transport. 

C. Cumulative Effects

The proposed research project is short-term (mid February to September) 

and would take place in a very limited area (approximately 1,400 acres 

within a 4,100 acre treatment area). APHIS is attempting to develop a 
22 

treatment protocol that would effectively eliminate ACP while also being 

effective against other citrus pests that are commonly treated. If 

successful, the utilization of such an efficient treatment protocol could 

decrease the gross amount of pesticides used in citrus groves with ACP. 

IV. Other Environmental Considerations 

A. Endangered Species Act 

Section 7 of the Endangered Species Act and its implementing regulations 

require Federal agencies to ensure their actions are not likely to jeopardize 

the continued existence of endangered or threatened species or result in 

the destruction or adverse modification of critical habitat. 

APHIS prepared a biological assessment that considered the impact of the 

proposed program on federally listed threatened and endangered species 

and designated critical habitat in Hidalgo County, Texas. Upon 

concluding the assessment, APHIS determined that the program would 

have no effect on the Texas ayenia and star cactus. APHIS also 

determined that the program may affect, but is not likely to adversely 

affect, the Gulf Coast jaguarundi, northern aplomado falcon, ocelot, and 

Walker’s manioc. APHIS requested concurrence with this determination 

from the U.S. Fish and Wildlife Service, Ecological Services Field Office 

in Corpus Christi, Texas, and received a concurrence letter dated 

February 9, 2009. No specific mitigation measures are required to protect 

listed species except for the northern aplomado falcon. To protect this 

species from disturbance, no aerial or ground treatments would be made 

within a 1⁄4-mile of occupied falcon nests. Aerial pesticide applications 

should be made in swaths parallel to a falcon nest and its aerial buffer 

zone. 

APHIS also received a report from Texas Parks and Wildlife indicating 

that there were no known occurrences of federal or state-listed species 

documented in the Texas Natural Diversity database within 1.5 mile of the 

proposed project area. 

B. Executive Orders 

Consistent with Executive Order (EO) 12898, “Federal Actions to Address 

Environmental Justice in Minority Populations and Low-income 

Populations,” APHIS considered the potential for the proposed action to 

have any disproportionately high and adverse human health or 

environmental effects on any minority populations and low-income 
23 

populations. Colonias6 are located within Hidalgo County. There is one 

colonia within the proposed treatment boundary; however, the colonia is 

not located within a citrus grove. There are six additional colonias located 

outside but adjacent to the treatment boundary. 

Due to the limited number of applications being applied to a limited area, 

as well as the labeled precautions that must be taken by applicators, 

APHIS has determined that the human health and environmental effects 

from the proposed applications are minimal and are not expected to have 

disproportionate adverse effects to any colonia or any other minority or 

low-income populations. 

Consistent with EO 13045, “Protection of Children from Environmental 

Health Risks and Safety Risks,” APHIS considered the potential for 

disproportionately high and adverse environmental health and safety risks 

to children resulting from the proposed action. Due to the limited number 

of applications being applied to a limited area, as well as the labeled 

precautions that must be followed by applicators, no exposure to children 

is expected to occur. It is the responsibility and obligation of the program 

pesticide applicators to ensure that the general public is not in or around 

areas being treated. This ensures that no exposure of the general public or 

children would occur during the application process. The only possible 

exposure would be to the applicator and nursery workers when not 

following the prescribed label use and safety directions. Therefore, it was 

determined that no disproportionate effects to children are anticipated as a 

consequence of implementing the proposed action alternative. 

 

6

 The term "colonia" in Spanish means a community or neighborhood. The Office of the Texas 

Secretary of State defines a "colonia" as a residential area along the Texas-Mexico border that may 

lack some of the most basic living necessities, such as potable water and sewer systems, electricity, 

paved roads, and safe and sanitary housing. 
24 

V. Agencies, Organizations, and 

Individuals Consulted 

U.S. Department of Agriculture 

Animal and Plant Health Inspection Service 

Policy and Program Development 

Environmental Services 

4700 River Road, Unit 149 

Riverdale, MD 20737 

U.S. Department of Agriculture 

Animal and Plant Health Inspection Service 

Plant Protection and Quarantine 

Emergency and Domestic Programs 

4700 River Road, Unit 134 

Riverdale, MD 20737 

U.S. Department of Agriculture 

Animal and Plant Health Inspection Service 

Plant Protection and Quarantine 

903 San Jacinto Blvd 

Austin, TX 78701 

U.S. Department of Agriculture 

Animal and Plant Health Inspection Service 

Plant Protection and Quarantine 

Center for Plant Health Science & Technology 

Mission Texas Laboratory 

Moore Air Base, Building 6414 

22675 N. Moorefield Road 

Edinburg, TX 78541 

Texas A&M University 

Kingsville Citrus Center 

312 N. International Blvd, 

Weslaco, TX 78596 

U.S. Fish and Wildlife Service 

Corpus Christi Ecological Services Field Office 

Texas A&M University-Corpus Christi 

6300 Ocean Dr. 

Cess Bldg. Rm. 118 

Corpus Christi, TX 78412 
25 

VI. References 

EPA—See U.S. Environmental Protection Agency 

Johnson, S. and P. Dureja. 2002. Effect of surfactants on persistence of 

azadirachtin a (Neem based pesticide). J. Environ. Sci. Health, B37(1), 

75–80. 

Kassir, J.T., Mohsen, Z.H. and N.S. Mehdi. 1989. Toxic effects of 

limonene against Culex quinquefasciatus (Say) larvae and its interference 

with oviposition. Anz. Schadlingskde., Pflanzenschutz, Umweltschutz 62, 

19-21. 

Solomon, K.R., Giddings, J.M., and Maund, S.J., 2001. Probabilistic risk 

assessment of cotton pyrethroids: I. Distributional analysis of laboratory 

aquatic toxicity data. Env. Toxicol. Chem. 20(3):652–659. 

Stark, J.D. and J.F. Walter. 1995. Persistence of azadirachtin A and B in 

soil: Effects of temperature and microbial activity. J. Environ. Sci. Health, 

Part B: Pest. Food Contam. Agric. Wastes. Vol. B30(5): 685-698. 

Thompson, D.G., Chartrand, D.T. and D.P. Kreutweiser. 2004. Fate and 

effects of azadirachtin in aquatic mesocosms—1: fate in water and bottom 

sediments. Ecotoxicology and Environmental Safety (59):186–193. 

USDA—See U.S. Department of Agriculture, Animal and Plant Health 

Inspection Service 

U.S. Department of Agriculture, Animal and Plant Health Inspection 

Service, 2005. Citrus greening eradication program pesticide applications 

human health and non-target species risk assessment, September, 2005. 

USDA, APHIS, Riverdale, Maryland. 

U.S. Department of Agriculture, Animal and Plant Health Inspection 

Service, 2008. Asian citrus psyllid cooperative control program chemical 

risk assessment—December 2008. USDA, APHIS, Riverdale, MD. 

U.S. Environmental Protection Agency, Office of Pesticide Programs. 

2009. OPP Ecotox Database. [Online]. Available: 

http://www.ipmcenters.org/index.cfm. [January 11, 2009]. 

U.S. Environmental Protection Agency, 2006. Human Health Risk 

Assessment: Aldicarb. Office of Pesticide Programs. 54 pp. 
26 

U.S. Environmental Protection Agency, 2005a. Aldicarb: Ecological 

Risk Assessment. Environmental Fate and Effects Division. Office of 

Pesticide Programs. 362 pp. 

U.S. Environmental Protection Agency, 2005b. Pyrethrins: Revised 

Human Health Risk Assessment for the Reregistration Eligibility 

Decision. 103 pp. 

U.S. Environmental Protection Agency, 2000. Kaolin Reregistration 

Eligibility Decision. Accessed January 7, 2009 at 

http://www.epa.gov/pesticides/biopesticides/ingredients/tech_docs/red_10

0104.htm. 

U.S. Environmental Protection Agency, 1994. Limonene Reregistration 

Eligibility Decision. Office of Pesticide Programs. 200 pp. 

Walker, M.M., and Keith, L.H., 1992. EPA’s pesticide fact sheet 

database. Lewis Publishers, Boca Raton, FL. 

World Health Organization. 2005. Environmental Health Criteria for 

Bentonite, Kaolin, and Selected Clay Minerals. Environmental Health 

Criteria 231.