Washington

Washington
Washington is within:
Country:	United States

Rangeland portal / Washington

Washington State, located in the Pacific Northwest region of the United States, is home to over 100 species of grasshoppers. A handful of pest species can have economic impacts on orchards and rangelands, especially in the central and eastern parts of the state.

State ecology

Highlighted species from Washington

Washington is characterized by diverse topography and ecosystems, ranging from the temperate rainforests of the Olympic Peninsula to the arid shrub-steppe of the Columbia Basin. This ecological variation supports a wide range of insect fauna, including numerous grasshopper species that play important roles in both natural and agricultural systems. Grasshoppers are particularly prevalent in the eastern part of the state, where the semi-arid climate and open rangelands create ideal habitat conditions. These insects are key components of grassland food webs, serving as prey for birds, mammals, and other invertebrates. However, under certain environmental conditions—such as warm, dry springs followed by hot summers—grasshopper populations can increase rapidly and become agricultural pests.

Commonly surveyed areas are situated within a broad inland basin between the Cascade and Rocky Mountains. This region has a diverse climate, with annual precipitation ranging from less than 10 inches in the arid south-central Columbia Basin to over 40 inches in the mountainous regions of the northeast and southeast.

Species of locust and grasshoppers in Washington represented in the HopperWiki

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Species of management concern

While Washington is home to over 100 grasshopper species, only a small number pose a threat to crops. In the Pacific Northwest, orchards are most commonly affected by the red-legged grasshopper (Melanoplus femurrubrum), clear-winged grasshopper (Camnula pellucida), and species in the Melanoplus genus especially the migratory grasshopper (Melanoplus sanguinipes). Among these, the red-legged grasshopper is particularly widespread and ranks as one of the most commonly encountered species. These grasshoppers are capable of defoliating trees and can also harm fruit and tender wood. Young trees are especially susceptible to this damage.

View U.S. Grasshopper Forecast Hazard Maps

Grasshopper management

Washington State Department of Agriculture, in collaboration with the USDA Animal and Plant Health Inspection Service (APHIS), monitors grasshopper populations annually and implements integrated pest management (IPM) strategies to mitigate damage. Management approaches in Washington emphasize early detection and ecological balance. Techniques include biological control agents such as parasitoid flies and predatory beetles, as well as targeted use of insecticides like diflubenzuron when thresholds are exceeded. Cultural practices, such as rotational grazing and habitat modification, are also employed to disrupt grasshopper breeding grounds and reduce the likelihood of outbreaks. Many different types of pesticides are used in orchards to control grasshoppers. Insecticides work best on younger, immature stages. The most effective approach is to target grasshoppers during their nymph stage by applying sprays or baits to areas surrounding the orchard.

Featured resource

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  Grasshopper management tips

Select photos from Washington

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Outbreaks

Outbreaks in Washington typically affect forage crops, rangeland grasses, and cereal grains, posing economic risks to ranchers and farmers. Significant grasshopper outbreaks typically happen once every 7 to 10 years, when conditions are particularly favorable for their growth and development. Since their populations grow gradually, it’s relatively simple to forecast years of high grasshopper activity. Outbreaks tend to be most severe when spring weather is warm and dry, and when the natural predators, parasites, and diseases that control grasshopper populations are scarce.

Grasshoppers reached destructive population levels in 1978-79.

Organizations

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Resources

Name	Year published	Resource link	Descriptive keyword	Language	Author
APHIS regulatory documents	2018		Early warning, Ecology, Public health, Social science, Culture, insecticide, Infestations, Environmental assessment, Rangeland management, Pesticides, Bundle, Environmental impact	English	Animal and Plant Health Inspection Service
ARS grasshopper species fact sheets	1994		Management, Species identification, Series	English	Agricultural Research Services, United States Department of Agriculture
Court rejects federal pesticide-spraying program on millions of acres of western rangelands	2025		Ecology, Spraying, Chemical control, Infestations, Management, Governance, Conservation, Land use management, Habitat	English
Field Guide to Common Western Grasshoppers	2002		Species identification, Field guide	English	United States Department of Agriculture, Robert E. Pfadt
Grasshopper infestation continues after pesticide spray canceled	2023		Spraying, Ecology, Environmental science, Infestations, Emergency response, Chemical control, Grazing	English	Alaina Mencinger
Grasshopper Integrated Pest Management User Handbook	2000		Biological control, Chemical control, Monitoring, Modeling, Population dynamics, Rangeland management, Decision making, Bundle, Ecology, Pesticides, Biopesticide, Integrated pest management	English	Agricultural Research Services, United States Department of Agriculture
Grasshopper management tips	2010	View	Grasshoppers, Biology, Management, Rangeland management, Crop health, Grazing, insecticide, Environmental assessment	English
Grasshopper watch	2022		Grasshoppers	English
Grasshoppers Are Descending on the West in Swarms	2021		Grasshoppers	English
Grasshoppers of the Western United States		View	Management, Species identification, Key	English	United States Department of Agriculture
Grasshoppers their habits and damage	1964	View	Grasshoppers, Outbreaks, Natural enemies, Ecology, Habitat, Quality illustrations, Species identification	English	United States Department of Agriculture
Hopper helper		View	Survey, Life cycle, Species identification, Integrated pest management	English	Wendal Cushing
Insect answers	1990	View	Species identification, Rangeland management, Infestations, Management, Chemical control, Biological control, Survey, estimation of grasshopper densities, Control, insecticide, Biology, Livestock, Weather	English	Daniel Suomi, Gary Thomasson, Dave Keim
Las Vegas resident shares experience as swarms of grasshoppers return to valley	2024		Outbreaks	English
Mega Disasters: Super Swarms of Locusts	2021		General locust education, Video	English
Montana.gov Orthoptera Field Guides		View	Species identification, Management, Biology, Distribution, Map, Rangeland management, Information hub, Website	English
Mormon cricket 'sludge' blankets northern Nevada roads causing crashes	2024		Media article, Outbreaks	English
Overview of the APHIS Rangeland Grasshopper and Mormon Cricket Suppression Program	2022		Management, Chemical control, Grasshoppers, Governance, Video	English	APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture
Overview of the APHIS Rangeland Grasshopper and Moron Cricket Suppression Program	2022		Video, Grasshoppers, Management, Educational video	English	United States Department of Agriculture, APHIS Plant Protection and Quarantine
Pest Grasshoppers of the West	2005	View	Management, Species identification	English	University of Wyoming
Protecting U.S. rangeland from grasshoppers and Mormon crickets	2021	View	Outbreaks, Infestations, Mormon crickets, Rangeland management, insecticide	English	United States Department of Agriculture
Rangeland Grasshopper and Mormon Cricket suppression program	2019	View	Public health, Governance, Culture, Grasshoppers, Economics, Environmental assessment, Life cycle, Biology	English	United States Department of Agriculture
Rangeland Grasshopper Management	1993		Management, Species identification, Control	English	University of Wyoming, Jeffrey Lockwood, Scott Schell
The Grasshoppers of the Western U.S. Lucid mobile app	2016		Management, Species identification	English	APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture, Center for Plant Health Science and Technology of the USDA
UC Integrated Pest Management for Home Gardeners and Landscape Professionals	2013	View	Life cycle, Pesticide management, Management	English	University of California Statewide Integrated Pest Management Program
USDA APHIS historical meeting report collection			APHIS archive 2024, Historical document, Annual report, Uncurated archive, Collection	English	United States Department of Agriculture, Animal and Plant Health Inspection Service
USDA APHIS-PPQ-Science & Technology Phoenix Lab Rangeland Unit project summary	2021		Summary, Set, Project, Project report	English, Spanish, French	APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), Animal and Plant Health Inspection Service, United States Department of Agriculture

Rangeland portal / Washington