The March of the Mormon cricket

Mormon crickets invaded Arlington, Oregon during the summer of 2017.

By Heidi Happonen


hey started crawling up the sides of houses in downtown Arlington. Three inches long and as wide as a finger, there ­were times during the infestation when 200 of them could be counted per square yard.

The year was 2017 and the Mormon crickets were devouring everything in their path – gardens, rangeland grasses, wheat fields, even each other.

“The Mormon cricket had always been in Blalock Canyon,” said Jordan Maley, an instructor in Oregon State University’s College of Agricultural Sciences Crop and Soil Science department and part of the Gilliam County Extension office, “but this was the first time they moved into downtown Arlington in such overwhelming numbers.”

Crickets everywhere

Maley and his colleagues sprang into action, calling a community meeting that included both residential homeowners and large area landowners. Immediate stop-gap measures were put in place using Integrated Pest Management practices that aimed to help protect homeowner’s property in such a way that wouldn’t harm the environment, the residents or their pets. A true community effort, volunteer April Aamodt organized residents and the local hardware store rallied to get organic bait, making crickets and grasshoppers sick when they ate it. And because crickets are cannibalistic, those that didn’t eat the bait directly, were also affected.

While that effort was underway, Maley reached out to the Oregon Department of Agriculture (ODA) to learn what products had been successfully used in other places. Based on ODA’s recommendation, rangeland owners eventually deployed an insect growth regulator known as Dimilin. As the insect changes shells, the Dimilin disrupts the process preventing them from changing into their adult form.

“To achieve economies of scale, we needed to manage the outbreak across ownership boundaries,” Maley said. “The county stepped up and paid for the program so that we could manage large areas of land across multiple ownerships.”

Maley also invited the Gilliam County Soil and Water Conservation District to participate in the program to provide mapping services which gave researchers a basis for looking at the relationships between Mormon cricket infestations and landscape types. Initial findings have shown Mormon crickets tend to be attracted to the soil in the north end of Gilliam county that is heavily influenced by the Missoula Floods—a cataclysmic glacial lake outburst of floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. While that research is still being analyzed, the sample points already have provided vital information to begin to inform a predictive tool to assist in survey work and management against future infestations.

In addition to the Dimilin application, some landowners also used SEVIN Bait, an insecticide-treated grain that affects an insect’s nervous system. And while these applications proved effective, the most powerful tool Maley discovered to combat the infestation was found in learning from the past.

Long-time Gilliam County resident Dick Krebs was a teenager during the last large scale Mormon cricket infestation in 1942. One of the largest landowners in the county, Krebs is still active in the community and was able to apply his historic knowledge to the problem to help devise longer-lasting innovative solutions.

“Dick’s perspective has been invaluable as he knew the circumstances of drought that preceded the infestation in both instances. He gave us the historical perspective, and this really was instrumental in getting other landowners to participate in the program.”

With the community engaged and on board, Maley approached the Gilliam County Court to appropriate $105,000 annually for the management effort.

“I wanted this to be a voluntary, land-owner driven program, so I assumed the role of facilitator and information manager, making sure people knew what was happening.”

The Oregon Department of Agriculture was also engaged, sending surveyors and trained volunteer April Aamodt into the field to count Mormon crickets and compile sample points from multiple locations within a GIS system that could then be formatted in Google Earth to make it easy to share.

“A big part of my role was making sure that survey information was compiled in understandable maps that could be quickly shared with participants,” Maley added. “Collaborating with different agencies, volunteers, local officials, and landowners to help facilitate solutions became my focus.”

While the current infestation has been largely addressed, it is not even close to over. Another challenge with the Mormon cricket is that the female will deposit her eggs about an inch below the soil – but those eggs don’t hatch all at once. They hatch over seven years.

“We know we are in this for the long haul,” Maley added. “We are committed to at least a seven-year program.”

To support that seven-year effort, Maley recently returned to the county government and was able to get an additional $246,000 approved to manage the problem on a longer-term basis.

While the plan and funding to execute the plan are in place, once present these insects can move­—up to ¼ mile per day. According to Maley, all indications point to them marching east toward high-value irrigated crops in Morrow County.

“We are already in talks with my Extension colleagues and local county leaders to prepare them for what is coming,” Maley said. “The success we’ve had here is entirely because of the willing participation and cooperation of people working as a team. That will be key in any place where the Mormon cricket decides to call home.”

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