Grasshoppers and Mormon Crickets
Plant Protection and Quarantine
May 2003
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 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 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 USDAís 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)Ý720-5964 (voice and
TDD). USDA is an equal opportunity provider and employer. <
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