‘Biblical’ swarms of giant Mormon crickets destroying crops in US West

Farmers in the American West are battling outbreaks of Mormon crickets — insects that can grow almost three inches (8cm) in length.

In the past few years the crickets, in addition to grasshoppers, have destroyed swathes of crops as officials spend millions trying to control the swarms, according to the Associated Press.

The climate crisis may be partly to blame. The insects prefer both hotter temperatures and droughts — conditions that are linked to global heating.

These outbreaks can be extraordinary, as the species often travels in groups of millions or billions of individual insects, says the US Department of Agriculture (USDA).

One rancher told AP that the swarms have been “truly biblical”.

Mormon crickets — technically a species of flightless katydids, and not official crickets — got their name after they ravaged crops planted by Mormon settlers in 19th century Utah.

As they march across the country, the insects devour vegetation, damaging crops and even changing patterns of erosion, water runoff and nutrient cycling, says USDA. Last year, 10 million acres in Oregon — which has been especially hard-hit by the species — were destroyed by Mormon crickets and grasshoppers.

Residents of affected areas describe roads slick with the remains of squished insects and fields damaged by the hungry creatures.

One Oregon rancher told AP that her land is “crawling with grasshoppers”, and that she had to spend tens of thousands of dollars on hay last year to make up for fields lost to the insects.

In response, officials have taken to spraying fields with pesticides. USDA says that the preferred option is to spray only some sections of field to reduce populations while leaving other sections untouched.

Oregon has also allocated millions of dollars to Mormon cricket and grasshopper suppression for private landowners. State officials can survey farms and ranches, and recommend spraying if they find more than three Mormon crickets or eight grasshoppers per yard – with landowners reimbursed for much of the pesticide costs.

But some environmental organizations have raised objections to the pesticide use. Last month, the Xerces Society, which focuses on insect conservation, and the non-profit Center for Biological Diversity sued one arm of the USDA over the spraying program.

Mormon cricket outbreaks can follow drought conditions, according to the Oregon state government, as warm weather and a lack of rainfall help the insects hatch and survive.

The US West is currently in the midst of a decades-long “megadrought” that has dried up water resources and challenged farming and ranching operations across the region.

These dry conditions are expected to get worse overall as the climate crisis deepens. Droughts are expected to be come both more frequent and more intense as the planet heats up.

The Associated Press contributed to this report