GRAND CANYON NATIONAL PARK, Ariz.— The federal Animal and Plant Health Inspection Service has cancelled plans to spray toxic insecticides to kill native grasshoppers within treasured and significant landscapes of the Colorado Plateau in northern Arizona.

Conservation groups blasted the plan, which would have allowed spraying inside portions the Vermilion Cliffs National Monument, Grand Canyon-Parashant National Monument, and the newly designated Baaj Nwaavjo I’tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument.

“This dangerous project could’ve decimated grasshopper species and many other plants and animals found nowhere else on Earth inside the national monuments created to protect them,” said Taylor McKinnon, Southwest director at the Center for Biological Diversity. “Cancelling the use of insecticides this year is a good start. But given the far-reaching threats insecticides pose across ecosystems, federal officials shouldn’t use them to target native species on any of our treasured public lands.”

APHIS oversees and funds the application of multiple pesticides on rangelands to prevent native grasshoppers and Mormon crickets from competing with livestock for forage.

The insecticides it proposed using — carbaryl, diflubenzuron and chlorantraniliprole — are indiscriminate. In addition to the grasshoppers the agency was targeting, the insecticides could also kill bees, moths and other insects. Spraying can harm entire ecosystems by disrupting pollination and can harm populations of birds, reptiles and mammals who feed on grasshoppers and insects.

One out of every 10 plant species in the Colorado Plateau region is an endemic species, meaning it’s found nowhere else on Earth.

The agency's draft environmental assessment omitted mention of the national monuments and unique species and habitats they were designated to protect. These species include rare bees, butterflies and other creatures found nowhere else, like the Kaibab monkey grasshopper and House Rock Valley chisel-toothed kangaroo rat, specifically named in the August proclamation establishing the Baaj Nwaavjo I’tah Kukveni National Monument.

Although grasshoppers and Mormon crickets can be locally abundant from time to time, native plants and other wildlife evolved with these cycles. Introducing pesticides to eliminate native grasshoppers is a shortsighted, quick fix that fails to consider the complex interrelationships within these delicate ecosystems.

The agency’s draft analysis showed that it failed to consult with affected Tribes with ties to the Grand Canyon area. The Grand Canyon Tribal Coalition, which proposed the Baaj Nwaavjo I’tah Kukveni National Monument, includes members of the Havasupai Tribe, Hopi Tribe, Hualapai Tribe, Kaibab Band of Paiute Indians, Las Vegas Tribe of Paiutes, Moapa Band of Paiute Indians, Paiute Indian Tribe of Utah, Shivwits Band of Paiutes, Navajo Nation, San Juan Southern Paiute Tribe, Yavapai-Apache Nation, Zuni Tribe and Colorado River Indian Tribes.

In March 2023 the U.S. Environmental Protection Agency published a draft biological opinion from NOAA Fisheries showing that carbaryl is likely to jeopardize 37 species protected under the Endangered Species Act and harm 36 designated critical habitats.

While Arizona is not home to any of the species named in that report, the findings show the extreme risk carbaryl poses to endangered fish and other species.

Potentially vulnerable endangered species in Arizona include Chiricahua leopard frogs, Western yellow-billed cuckoos, Gila chub, black-footed ferrets and Siler pincushion cacti.