Remember wireworms? Of course you do. It wasn’t so long ago the pesky critters which come in 14 different species in the Pacific Northwest, were eating many farmers’ lunch as they ate the roots of wheat plants.

Numerous stories in Wheat Life have described the problem, which began with loss of the chemical Lindane in 2006. Newer generation seed treatments called neonicotinoid (neonics) appeared to deter the worm, but not kill it.

The Washington Grain Commission acted quickly, assigning the Washington Wheat Distinguished Professorship, a $1.5 million endowment, to Washington State University entomologist Keith Pike in 2011. David Crowder took over the project upon Pike’s retirement.

Pike assembled a team of researchers from around the Northwest, including Montana, to map wireworms, determine their species and destructiveness, and conduct research looking at chemical controls, including the proper threshold for neonic seed treatments. Although the distinguished chair funding has now been assigned to another WSU researcher, the wireworm effort continues to receive WGC funding as a separate $60,000 line item.

Aaron Esser, Washington State University Extension regional agronomist

Aaron Esser, Washington State University Extension regional agronomist

In episode 26 of the Wheat All About It! podcast, (available on iTunes and the WGC website at wagrains.org) Aaron Esser,  WSU extension regional agronomist based in Ritzville, said the distinguished chair funding from the WGC “did its job” in helping researchers learn much more about wireworms and how to control them.

“We really ramped up and learned a lot more about the species. That went a long way to learning more about what we are dealing with. It was tremendous,” he said.

In the podcast, Esser noted the moment his wireworm project started: June 14, 2008. That’s the day he came upon a field that had been ravaged by the larval form of the click beetle despite the application of a seed treatment.

“That’s when I realized we had something a lot bigger going on,” he said.

Esser initially believed that neonics seed treatments against wireworms were suppressive, but did not affect their numbers in the field. Based on the progress made over the last nine years, which has included guiding chemical companies to higher neonic thresholds, he now believes higher rates do increase wireworm mortality.

“We see reduced populations, I’m assuming it is mortality. but the portion of the study didn’t look at counting dead wireworms,” he said, adding, “There were significantly less wireworms the following year. I assume they are dead.”

Although it appears the corner has been turned in the battle against wireworms, Esser said it’s important farmers and fieldmen understand what wireworm damage looks like as well as which species predominates on a specific farm.  In Eastern Washington the three main species are Limonius infuscatus, also known as the western field wireworm, Limonius californicus, known as the sugarbeet wireworm and Selatosomus pruininus, known as the great basin wireworm.