APHIS Factsheet

Plant Protection and Quarantine May 2010

Grasshoppers and 

Mormon Crickets

Rangeland in the Western United States is a 

valuable agricultural resource for livestock production 

and provides an important habitat for wildlife. 

Grasshoppers and Mormon crickets (hereafter, 

referred to collectively as grasshoppers) are natural 

components of this ecosystem. However, their 

populations can reach outbreak levels and cause 

serious economic losses to rangeland forage, 

especially when accompanied by a drought.

Not all grasshopper species signi! cantly damage 

rangeland forage, so action to protect rangeland 

resources is not always required when grasshopper 

populations increase. However, a rapid and effective 

response is required when a grasshopper outbreak 

develops and threatens rangeland forage. During such 

an event, Federal land management agencies, State 

agriculture departments, county and local governments, 

private groups, and/or individuals can request 

assistance from the U.S. Department of Agriculture’s 

(USDA) Animal and Plant Health Inspection Service 

(APHIS) to suppress rangeland grasshopper 

populations. Under the Plant Protection Act (PPA), 

APHIS has the authority, subject to funding availability, 

to treat Federal, State, or private lands that have 

economically signi! cant infestations of grasshoppers.

Grasshopper and Mormon Cricket Biology

Grasshoppers and Mormon crickets are closely related 

insects that belong to the Order Orthoptera. Nearly 

400 grasshopper species inhabit the 17 Western 

States involved in APHIS’ grasshopper program, but 

only a small percentage are considered pest species. 

Anywhere from 15 to 45 species of grasshoppers 

can be found in a particular rangeland ecosystem, 

and economic damage usually occurs as a result of 

grasshoppers increasing in number. 

Mormon crickets (Anabrus simplex) are " ightless, 

shield-backed katydids. Although they do not " y, 

Mormon crickets are highly mobile and capable of 

migrating great distances. They move in wide bands 

by walking or jumping, and may devour much of the 

forage in their path. 

Both insects damage grasses and other 

vegetation by consuming plant stems and leaves. 

Their feeding causes direct damage to plants’ growth 

and seed production, thus reducing valuable livestock 

forage. Other effects of these pests include: soil 

erosion and degradation, disruption of nutrient cycles, 

interference with water ! ltration, and potentially 

irreversible changes in the " ora and fauna of the 

rangeland ecosystem. In addition, some populations 

that develop on rangelands can invade adjacent 

cropland where the value of crop plants is much 

higher than that of rangeland grasses. 

APHIS’ Grasshopper Program 

APHIS conducts surveys for grasshopper populations 

on rangeland in the Western United States, provides 

technical assistance on grasshopper management to 

landowners and managers, delivers public outreach 

and education programs, and may cooperatively 

suppress grasshopper populations when direct 

intervention is necessary. APHIS treats grasshoppers 

only upon request and after determining that treatment 

is warranted. In some cases, APHIS rangeland 

treatments protect not only the rangeland, but also 

reduce the likelihood that the grasshoppers will move 

into crops and other lands that border rangeland.

APHIS surveys grasshopper populations in the 

following Western States: Arizona, California, Colorado, 

Idaho, Kansas, Montana, Nebraska, Nevada, New 

Mexico, North Dakota, Oklahoma, Oregon, South 

Dakota, Texas, Utah, Washington, and Wyoming. 

Survey information is used by APHIS and land 

managers and owners to assess whether treatments 

may be warranted. Treatment must be requested by 

a Federal land management agency, State agriculture 

department, county or local government, private group, 

and/or individual that has jurisdiction over the land 

before APHIS can begin to consider a treatment.

Upon request, APHIS would visit the site and 

assess various factors relevant to the infestation to 

determine whether action by APHIS is warranted. 

These factors include, but are not limited to, the pest 

species, biological stage of the species, timing of 

the treatment, treatment and chemical options, cost 

bene! ts of conducting the action, and ecological 

considerations. Grasshopper surveys, conducted 

at certain times of the year, may show the potential 

for large grasshopper populations. Based on survey 

results, county, State, and Federal officials and/or 

rancher groups may initiate early coordination of local 

programs and request APHIS assistance in a timely 

and effective cooperative effort.

Cooperative Suppression of Grasshoppers 

Federal agencies own or manage approximately 

43 percent of the rangeland in the United States. 

The U.S. Department of the Interior’s Bureau of 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture

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

in all its programs and activities on the basis of race, color, national 

origin, age, disability, and where applicable, sex, marital status, 

familial status, parental status, religion, sexual orientation, genetic 

information, political beliefs, reprisal, or because all or part of an 

individual’s income is derived from any public assistance program. 

(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 ! le a complaint of discrimination, write to USDA, Director, Office 

of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 

20250–9410, or call (800) 795–3272 (voice) or (202) 720–6382 

(TDD). USDA is an equal opportunity provider and employer. 

Land Management, the Bureau of Indian Affairs or 

individual Tribes, and USDA’s Forest Service are 

among the principal managers of the rangeland. 

Federal rangeland eligible for cooperative grasshopper 

suppression treatments from APHIS includes: areas 

with widespread outbreaks; areas with developing 

populations or “hot spots” (lands with high densities of 

egg masses) of grasshoppers, that, if treated, would 

prevent a wider spread of outbreaks; and Federal or 

Trust land borders that, if treated, would prevent the 

movement of economically threatening populations of 

grasshoppers to adjacent private agricultural lands. 

APHIS, at the request of Federal land managers, 

may conduct grasshopper suppression treatments 

on federally managed rangeland when traditional 

practices fail to keep populations below economic 

thresholds. After receiving a land manager’s request 

for grasshopper assistance and assessing the 

availability of funds, APHIS determines the need for 

suppression treatments on Federal rangelands. 

APHIS is involved with grasshopper suppression 

treatments on Federal, State, and private rangeland 

as part of a cost–sharing program established by the 

PPA. On Federal lands, APHIS pays 100 percent of 

the treatment cost. On State lands, APHIS provides 

50 percent of the funds for treatment and control, 

and the State provides the remaining 50 percent. On 

private rangelands, APHIS provides 33 percent of 

the funding, with the State and/or private landowner 

paying the remainder of the treatment cost. This 

cost share is only available if APHIS conducts 

the suppression treatments. During outbreaks, 

many grasshopper treatments will be conducted 

independently from APHIS’ program.

APHIS does not have the authority to conduct 

suppression programs for grasshoppers on private 

crop lands. However, if small amounts of croplands 

(typically less than 15 percent of the treatment area) 

are interspersed in a rangeland treatment block, 

APHIS could treat the entire block in order to maintain 

the continuity of the spray program. The insecticide, 

however, must be labeled for use on that crop. In such 

cases APHIS would charge the private crop grower 100 

percent of the treatment cost for the treated crops.

APHIS does conduct rangeland treatments 

in areas where federally administered rangeland 

is adjacent to crops. This not only protects the 

rangeland forage but also prevents grasshoppers from 

moving into the adjacent crops. In these situations, 

APHIS does not treat the crops, and the crop owner is 

responsible for any treatments that may be needed.

Treatment Options 

In 2002, APHIS completed the Rangeland 

Grasshopper and Mormon Cricket Suppression 

Program Final Environmental Impact Statement (EIS). 

The EIS considered three alternatives for managing 

grasshopper/Mormon cricket populations. The 

alternatives are: no APHIS control action, insecticide 

applications at conventional rates and complete 

area coverage, and reduced agent area treatments 

(RAATs), an approach that treats less land area and 

uses insecticides at lower rates. The RAATs strategy 

relies on the efficacy of an insecticide to suppress 

grasshoppers within directly treated swaths—and the 

natural movement of grasshoppers into the treated 

swath as they forage—while conserving grasshopper 

predators and parasites in alternating untreated areas. 

The insecticides available for used by APHIS 

in the grasshopper program include carbaryl, 

di" ubenzuron, and malathion. Treatment would 

consist of a single application of only one of 

these three. All of these effective insecticides are 

currently registered for use and labeled by the U.S. 

Environmental Protection Agency for control of 

rangeland grasshoppers. The insecticide chosen 

depends on a number of factors, including: species 

of grasshopper/Mormon cricket, age of population, 

climate, weather, forage condition, economics, and 

environmental risks.

Each of the insecticides is very effective and 

safe when used properly under the right conditions, 

and APHIS conducts environmental assessments in 

each State before any actions occur. APHIS follows 

all insecticide label directions, along with conditions 

outlined in the EIS, the environmental assessment, 

grasshopper program guidelines, and the original 

treatment request letter.

Additional Information 

For additional information on APHIS’ grasshopper 

program, please visit the APHIS Web site at www.

aphis.usda.gov, or contact your State Plant Health 

Director (SPHD). You can ! nd contact information for 

your SPHD on APHIS’ Web site at http://www.aphis.

usda.gov/services/report_pest_disease/report_pest_

disease.shtml.