Grasshoppers and

Mormon Crickets

Rangeland in the western United States is an 

important agricultural resource because of the forage

production used for livestock feed. Grasshoppers

and Mormon crickets (hereafter, referred to 

collectively as grasshoppers) are natural components

of the rangeland ecosystem. However, their populations can reach outbreak levels and cause serious

economic losses, especially when accompanied by a

drought. Land managers utilize integrated pest 

management techniques including grazing management, cultural and mechanical methods, prescribed

burning, and other techniques to dampen the growth

of grasshopper populations and prevent outbreaks.

Despite the best land management efforts,

grasshopper infestations often cover vast acreage,

and individual landowners may not have the

resources to control these infestations and therefore,

must rely on Federal support. The U.S. Department

of Agriculture’s (USDA) Animal and Plant Health

Inspection Service (APHIS) is the Federal agency

responsible for controlling economic infestations of

grasshoppers on western rangelands with a cooperative suppression program.

Grasshopper and Mormon Cricket

Biology

Grasshoppers and Mormon crickets are closely

related insects that belong to the Order Orthoptera.

Grasshoppers are winged and may have long or

short horns. Most species are highly mobile due to

their strong jumping legs and ability to fly.

Nearly 400 species of grasshoppers inhabit the

17 Western States involved in APHIS’ grasshopper

program. 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 several grasshopper species inhabiting an

area.

Mormon crickets, classified as Anabrus simplex,

are flightless, longhorned grasshoppers. Although

they do not fly, Mormon crickets are highly mobile

and capable of migrating great distances. They move

in wide bands by walking or jumping, devouring 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 forage and

feed for livestock. Other effects of these pests

include: soil erosion and degradation, disruption of

nutrient cycles, interference with water filtration, and

potentially irreversible changes in the flora and fauna

of the rangeland ecosystem. In addition, populations

that develop on rangelands can invade adjacent 

cropland where the value of crop plants is much 

higher than rangeland grasses.

APHIS’ Grasshopper Program

The goal of APHIS’ grasshopper program is not

to eradicate them but to reduce outbreak populations

to less economically damaging levels. In these

States, APHIS conducts field surveys of grasshopper

populations, provides technical assistance to

landowners, and conducts suppression treatments

when necessary and when funds are available.

Effective surveys are an essential measure in

order to determine the extent of grasshopper infestations and to determine the need for suppression

treatments. APHIS conducts these activities 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.

APHIS personnel conduct surveys of early 

season populations of immature grasshoppers and

surveys of adult grasshoppers in mid to late season

to assess if suppression programs are warranted.

APHIS utilizes nymphal survey data for treatment

decisions, and the adult survey data for forecasting or

predicting where potential grasshopper problems may

occur in the spring or early summer of the next 

growing season.

APHIS also provides States and cooperators with

technical assistance on grasshopper control, including guidance on the timing of control treatments,

organizing local control programs, and information on

the availability of new treatment methods.

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 Land

Management (BLM), the Bureau of Indian Affairs

(BIA), and USDA’s Forest Service (FS) are among

the principal managers of the rangeland. Federal

rangeland eligible for cooperative grasshopper suppression treatments from APHIS includes: rangeland

blocks of more than 10,000 acres that would protect

forage as well as prevent re–infestation if treated;

incipient populations, or hot spots of grasshoppers,

that, if treated, would prevent a wider spread of outFactsheet

Plant Protection and Quarantine May 2003

APHIS
breaks; 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 BLM, may conduct

grasshopper suppression treatments on federally

managed rangeland when traditional practices fail to

keep populations below economic thresholds. After

receiving a landmanager’s requests for grasshopper

assistance and assessing the availability of funds,

APHIS decides on the need for suppression treatments on Federal rangelands.

In addition, APHIS contributes to the control of

grasshoppers on State and private rangeland as part

of a cost–sharing program set by the Plant Protection

Act (PPA). State and private rangeland are eligible for

suppression programs similar to those of Federal

rangelands. 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 private landowner paying

the remainder. APHIS does not have the authority to

conduct suppression programs for grasshoppers on

private cropland or on private rangeland borders for

crop protection.

Treatment Options

In 2002, APHIS completed the Rangeland

Grasshopper and Mormon Cricket Suppression

Program Environmental Impact Statement (EIS). The

EIS considered three alternatives for managing

grasshopper/Mormon cricket populations. The alternatives are as follows: no APHIS control action; insecticide applications at conventional rates and complete

area coverage, and reduced agent area treatments.

APHIS conducts an environmental assessment in

each State. This assessment determines which alternative is chosen.

The insecticides utilized by APHIS in the

grasshopper program include carbaryl, diflubenzuron

and malathion. All of these effective insecticides are

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

Environmental Protection Agency for rangeland 

control of grasshoppers. The pesticide 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 pesticides is very effective and safe

when used properly under the right conditions.

APHIS follows all pesticide label directions, along with

conditions outlined in the EIS, the environmental

assessment, grasshopper program guidelines, and

the original treatment request letter from the land

management agency.

APHIS applies insecticides by ground equipment

by distributing baits usually made of wheat bran or

rolled oats and carbaryl or aerially by distributing

ultra–low–volume applications (any application of less

than .5 gallons per acre). When using the

ultra–low–volume applications, APHIS and its cooperators take every necessary precaution to control spray

distribution to avoid drift or off–target movement of the

material. No insecticides are applied directly on

water, and buffers are established around sensitive

sites.

An alternative to full coverage insecticide treatment is the Reduced Area and Agent Treatments

(RAATs) approach, which treats less land area and

uses insecticides at lower rates. The RAATs strategy

relies on the efficacy of an insecticide to suppress

grasshoppers within treated swaths, while conserving

grasshopper predators and parasites in untreated

areas.

Environmental Documents

As required under the National Environmental

Policy Act of 1969 (NEPA), APHIS prepares the 

necessary environmental documents for all of its

grasshopper suppression programs conducted in all

or part of the 17 Western States. These documents

include the EIS of programmatic actions of grasshopper suppression, site–specific environmental assessments, and national or local Section 7 consultations

with the U.S. Fish and Wildlife Service or National

Marine Fisheries Service on necessary protective

measures for non–target impacts on threatened and

endangered species.

Additional Information

For additional information on APHIS’ grasshopper 

program, please visit the APHIS Web site at

www.aphis.usda.gov or contact your State’s plant

health director or agriculture regulatory official.

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, 14th and

Independence Avenue, SW, Washington, DC 20250–9410 or call

(202) 720–5964 (voice and TDD). USDA is an equal opportunity

provider and employer.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture