RELEASE: Lawsuit Challenges Federal Pesticide-Spraying Program Affecting Millions of Acres of Western Rangelands

For Immediate Release, May 31, 2022


Sharon Selvaggio, Xerces Society for Invertebrate Conservation, (503) 704-0327, [email protected]

Scott Hoffman Black, Xerces Society for Invertebrate Conservation, (503) 449-3792, [email protected]

Andrew Missel, Advocates for the West, (503) 914-6388, [email protected]

Lori Ann Burd, Center for Biological Diversity, (971) 717-6405, [email protected] 

WASHINGTON— The Xerces Society and Center for Biological Diversity sued the federal Animal and Plant Health Inspection Service today over its program allowing insecticide spraying on millions of acres in 17 western states.

APHIS, a highly secretive agency within the U.S. Department of Agriculture, oversees and funds the application of multiple pesticides on rangelands to prevent native grasshoppers and Mormon crickets from competing with livestock for forage.

Federal regulators have failed to properly assess the broad environmental impacts of the spraying, as required by the National Environmental Policy Act, according to the conservation groups.

The lawsuit focuses on the harm from the insecticide spray program in Montana, Wyoming, Oregon and Idaho — states that have experienced heavy spraying under the program.

In 2021 APHIS released bids for contracts to aerially spray areas measuring more than 2.6 million acres just in Montana, with one spray block measuring nearly a million acres. In recent years, pesticide spraying has occurred within national wildlife refuges, popular public recreation areas, endangered species habitats and adjacent to wilderness areas.

“Over 80% of animals in rangelands are insects and they are the backbone of ecosystems; providing pollination, food for birds such as sage grouse and helping clean up waste from animals,” said Scott Black, executive director at the Xerces Society. “These broad-scale pesticide applications could have major negative impacts not only on the grasshoppers that are targeted but on wildlife broadly.”

Insects contribute services valued at more than $70 billion per year to the U.S. economy, according to a recent study. People and wildlife depend on insect pollination for fruits, vegetables, nuts and seeds. Most birds, freshwater fish and mammals consume insects as food.

Greater sage grouse, monarch butterflies, western bumblebees and a wide variety of other species that inhabit western grasslands are already in steep decline and are extremely vulnerable to further harm from APHIS’s insecticide-spraying program.

Insects, including grasshoppers, are a critical part of the diet of sage grouse chicks. But APHIS’s spraying program does not take any steps to protect the imperiled birds from harm unless it is requested by landowners. Once numbering in the millions, greater sage grouse populations have declined by more than 90%.

“In APHIS‘s telling, its program magically affects only grasshoppers, and only as much as necessary,” said Andrew Missel, staff attorney at Advocates for the West, which is representing the conservation groups. “But that’s not how pesticides work; blanketing hundreds of thousands or even millions of acres of rangelands with broad-scale pesticides kills bees, butterflies, moths, beetles and other vital species, and threatens to further impair ecosystems already suffering from the effects of drought and climate change.”

The main insecticide sprayed is diflubenzuron, which kills a wide variety of juvenile insects. It is typically sprayed from airplanes over areas of at least 10,000 acres. The label for the product warns against exposing bees and western rangelands are home to the estimated 600 to 1,000 species of native bees. Aquatic invertebrates that serve as important food for imperiled fish species are also vulnerable to harm from diflubenzuron.  

“APHIS is out of control, spraying deadly poisons on biodiversity hotspots like Oregon’s Malheur National Wildlife Refuge, which is visited by tens of thousands of people each year eager to see the incredible diversity of birds and wildlife there,” said Lori Ann Burd, environmental health director at the Center for Biological Diversity. “It’s time for this outlaw arm of the USDA to be held accountable for actively contributing to the escalating extinction crisis.”

The public supports protection for wildlife and is especially concerned with the welfare of pollinators, which are harmed by the spray programs. Eighty percent of western voters agree that loss of pollinators is a serious problem, according to a 2020 Colorado College poll. This concern held true in every state and across all types of communities: cities (85%), suburbs (81%), small towns (77%), and rural areas (76%).

Other insecticides approved for use in the spraying program include highly toxic carbaryl and malathion and a newer insecticide, chlorantraniliprole. The Environmental Protection Agency has determined that carbaryl is likely to harm 1,640 listed species, or 91% of all endangered plants and animals. It found that malathion is likely to harm 1,835 listed species, or 97% of all endangered plants and animals.

Chlorantraniliprole is a systemic pesticide absorbed by plants and moving to leaves, pollen and nectar, potentially exposing bees and butterflies for an extended time. Studies show it is highly toxic to monarch butterflies and other caterpillars.

Today’s lawsuit, filed in the U.S. District Court in Portland, Oregon, follows a 60-day notice of intent filed by the groups last week to sue APHIS for failing to properly consider harms to endangered species caused by the insecticide spraying. At the conclusion of the 60-day period, the lawsuit will be amended to include the group’s claims regarding the failure to fully assess the harms of the spraying program to protected species.

More than 230 species protected by the Endangered Species Act may inhabit the areas where spraying is authorized under the APHIS program, including yellow-billed cuckoos, black-footed ferrets, bull trout, Ute ladies’-tresses orchids, Oregon spotted frogs and Spalding’s catchflies.

APHIS claims that it enforces buffers to ensure that residential areas, organic farms and beehives are protected. But emails to APHIS from landowners who observed impacts of the aerial pesticide spraying indicate that samples detected the pesticides on private property beyond the spray buffers.

The states in which the insecticide spraying is approved include Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington and Wyoming.


The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

The Xerces Society is a nonprofit organization that protects the natural world by conserving invertebrates and their habitat. Established in 1971, the Society is a trusted source for science-based information and advice and plays a leading role in promoting the conservation of pollinators and many other invertebrates. 

Advocates for the West is a public interest, nonprofit environmental law firm that protects and defends the West’s public lands, waters, fish and wildlife.

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