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Frequently Asked Questions About
Grasshoppers and Mormon Crickets
in Western States
Last Modified:
What impact do grasshoppers and Mormon crickets have on rangeland, agriculture, and the
environment?
Grasshoppers and Mormon crickets are natural components of the rangeland
ecosystem; however, when their populations reach outbreak levels, they cause
serious economic losses to U.S. agricultural resources—particularly in warm, dry
conditions. APHIS cooperates with Federal, State, Tribal, and local agencies,
organizations, and institutions to conduct survey and suppression activities in
Western States to reduce grasshopper and Mormon cricket damage and protect
valuable agricultural resources and rangeland. The monetary value of rangeland for
livestock forage, recreation, carbon sequestration, and other ecosystem services is
estimated to be between $10.7 billion to $21.2 billion (according to a 2012 Economic
Analysis prepared by the University of Wyoming through a cooperative agreement
with APHIS).
Uncontrolled infestations could cause significant economic losses for U.S. livestock
producers by reducing forage available on rangeland, forcing producers to buy
supplemental feed or sell their livestock at reduced prices. Besides feeding on
grasslands, large grasshopper and Mormon cricket populations can also devastate
cultivated crops such as alfalfa, barley, corn, and wheat.
Grasshopper outbreaks can cause significant losses to beekeepers, and their
colonies can suffer losses as well when grasshoppers destroy bee rangeland food
sources. Beekeepers are then forced to move their hives or buy alternative food
sources to sustain them. They can also experience greatly reduced honey
production during these times. Grasshopper outbreaks likely impact wild pollinators
similarly by destroying or reducing flowering plants.
Rangeland provides recreation areas and opportunities for the public that can also
be negatively impacted by grasshopper population outbreaks and the widespread
damage they cause. Damage from grasshoppers and Mormon crickets also reduces
habitat and food sources for wildlife, which can threaten animal and plant
biodiversity as well as the rangeland’s ability to sequester carbon.
Benefits derived from suppressing outbreak populations are diverse and include:
Protection of adjoining cropland;
Forage preservation for wildlife;
Habitat sustainment for threatened and endangered species;
Protection of fragile soils;
Safeguards to reforestation efforts and social and recreational value; and
Highway traffic safety, which large masses of Mormon crickets on the roadways
can compromise.
Are these invasive or domestic grasshoppers and Mormon crickets?
Low levels of grasshopper and Mormon cricket populations are natural components
of the rangeland ecosystem; however, when their populations reach outbreak levels,
they cause serious economic and environmental losses. Nearly 400 grasshopper
species inhabit the Western United States, but only a small number of them (12
species, in particular) are considered pests, with varying numbers and combinations
of species found in a given rangeland ecosystem. The Mormon cricket (Anabrus
simplex) is the only katydid species known to hatch outbreak populations in the
United States.
Is there a difference between grasshoppers and Mormon crickets in terms of the rangeland
damage or treatment?
Grasshoppers and Mormon crickets belong to the insect order Orthoptera.
Rangeland grasshoppers are ground-dwelling insects with powerful hind legs that
enable them to escape from threats by leaping vigorously. Most species also have
wings that allow them to fly relatively long distances. They are sometimes referred
to as “short-horned” grasshoppers. Mormon crickets are flightless, shield-backed
katydids. Although they cannot fly, Mormon crickets move in large groups made up
of millions or billions of individual insects, and can migrate great distances.
Grasshoppers and Mormon crickets damage grasses and other vegetation by
consuming plant stems and leaves, damaging plant growth and seed production.
This reduces valuable livestock forage, and can lead to other environmental effects,
including soil erosion and degradation, disruption of rangeland nutrient cycles,
interference with rangeland water filtration, and potentially irreversible changes in
the rangeland ecosystem. In addition, some populations that develop on rangelands
can invade adjacent cropland where the value of traditional crop plants is often
much higher than that of rangeland grasses.
How does APHIS assist landowners and managers experiencing grasshopper and Mormon
Cricket outbreaks and who is eligible for treatment?
APHIS helps Federal, State, and private landowners in 17 Western States manage
grasshopper and Mormon cricket damage on rangeland by providing information
about population levels, conducting suppression treatments where possible, and
providing technical assistance.
APHIS and cooperators share the costs of providing suppression treatments on
rangelands, in compliance with Section 7717 of the Plant Protection Act. APHIS
treats grasshoppers only upon request, and after determining that treatment is
warranted. When a Federal land management agency, Native American tribe, State
agriculture department, county or local government, private group, or individual
with jurisdiction over the land makes a written request for grasshopper treatment,
APHIS visits the site and assesses various factors to determine whether action is
necessary.
These factors include grasshopper densities per yard, the pest species and its
biological stage, treatment timing and options, and other ecological considerations,
among others. County, State, and Federal officials, Tribes, and/or rancher groups
may also initiate cooperative local programs and request APHIS assistance when
surveys show the potential for large grasshopper populations.
APHIS does not have the authority to conduct grasshopper suppression treatments
on private crop lands. However, APHIS conducts rangeland suppression treatments
in areas where federally managed rangeland is immediately adjacent to private crop
lands. This protects rangeland forage, and prevents grasshoppers and Mormon
crickets from moving into adjacent crops. In these circumstances, APHIS only treats
the adjacent rangeland, and the crop owner is responsible for treating their
croplands, if desired.
Who pays for the treatment?
When treatment is necessary, APHIS shares the costs of providing suppression
treatments on rangelands in compliance with Section 7717 of the Plant Protection
Act. On Federal and Tribal Trust rangelands, APHIS pays 100 percent of treatment
costs. On State lands, APHIS provides 50 percent of the treatment costs, and the
State provides the remaining funds. On private lands, APHIS provides 33 percent of
the treatment costs, with the State and/or private landowner responsible for paying
the remainder. Cost shares are only available if APHIS conducts the suppression
treatments.
What do APHIS’ grasshopper and Mormon cricket treatments consist of?
APHIS uses the Reduced Agent and Area Treatments (RAATs) method when
conducting treatments. This method applies treatments to alternating swaths of
land, decreasing the amount of insecticide used by reducing the amount of area
treated (usually by at least 50 percent). Since the early 2000s, APHIS has used
RAATs on approximately 99% of the acres we have treated. The RAAT strategy relies
on an insecticide’s ability to suppress grasshoppers and/or Mormon crickets within
treated swaths—and the natural movement of grasshoppers into the treated swath
as they forage—while reducing the impact to grasshopper predators and parasites in
the alternating untreated swaths.
APHIS is using diflubenzuron to conduct a majority of the treatments. It is a chitin
inhibitor which prevents the growth of the immature grasshoppers and/or Mormon
crickets after it is ingested. The application methods and drift mitigation measures
are designed to allow treatments to reach the plants as quickly as possible, so
chemicals don’t linger in the air and are less prone to drift. APHIS applies
diflubenzuron at rates well below the maximum allowable rate specified on the label
and only one time a year within a treatment area.
When does APHIS begin grasshopper and Mormon cricket suppression treatment?
Timeframes vary from state-to-state. However, APHIS generally starts suppression
treatments in the late spring, and will continue into the summer. In most Western
states, the prime time to treat grasshoppers and/or Mormon crickets is in June and
July before their populations reach adulthood, and when they begin to lay eggs that
would hatch the following year. APHIS primarily uses diflubenzuron, an insect growth
regulator treatment, to target young grasshoppers.
How can people get involved if they need some kind of assistance?
They can also reach out to their USDA State Plant Health Directors for guidance on
certified applicators. USDA provides outreach and planning meetings starting in the
fall, through the winter, to prepare for and be positioned to respond if needed the
following year.
What environmental safeguards does APHIS employ when treating?
APHIS is committed to being a good steward of the environment and following the
National Environmental Policy Act (NEPA).
Environmental Impact Statement and Environmental Assessments
APHIS prepares environmental assessments (EA) as required under NEPA to evaluate
the impacts of the various alternatives proposed by APHIS to suppress grasshopper
and Mormon cricket populations. An EA is prepared in each State, or for
geographically similar portions of a State where the program may operate. The EA is
made available to the public for review during a 30-day comment period. The EAs
are tiered to the environmental impact statement that was completed in 2019.
U.S. Fish and Wildlife Service Consultation
In addition, APHIS conducts local consultations with the U.S. Fish and Wildlife Service
to ensure compliance with Section 7 of the Endangered Species Act. During the
consultation, both agencies agree on mitigation measures to protect threatened and
endangered species and their designated critical habitat.
Monitoring
The program’s integrated pest management strategy includes grasshopper
population monitoring, and we only treat outbreaks that will be harmful to
rangeland. We minimize the potential for drift and volatilization by not using ultra-
low volume sprays when the following conditions exist in the treatment area:
Wind sustained velocity exceeds 10 miles per hour (unless State law requires
lower windspeed)
Rain is falling or is imminent
Dew is present over large areas within the treatment block
There are temperature inversions near the ground surface that could affect the
spray deposition
The grasshopper program does not apply insecticides directly to water bodies such
as reservoirs, lakes, ponds, pools left by seasonal streams, springs, wetlands, and
perennial streams and rivers. The program also follows all other label restrictions
designed to protect aquatic habitats. Furthermore, we provide the following
distance buffers from water bodies:
500-foot buffer with aerial liquid insecticide
200-foot buffer with ground liquid insecticide
200-foot buffer with aerial bait
50-foot buffer with ground bait
PPQ uses environmental residue monitoring to assess application success and
determine if our mitigation measures protect sensitive habitats, including aquatic
habitats.
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