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Weed & Pest

USDA APHIS assists with surveys, treatment of grasshoppers in Wyoming


With an estimated 3,000 survey stops across Wyoming in 2010, USDA APHIS’s Plant Protection and Quarantine (PPQ) division intensively monitors grasshopper populations throughout the state.
“In 2009 they said a grasshopper outbreak was coming, and they were on the mark,” says Natrona County Weed and Pest District Supervisor Brian Connely. “They were able to help us gear up for 2010.”
Since 1934 Congress has charged the agency with the suppression of grasshoppers on rangeland.
“Our role in grasshopper management is three-pronged. The first is surveys of both the nymphal and adult stages, even in the down years. The second is technical assistance by providing site visits and options, and the third is treatments, including cost-shared suppression programs,” says Justin Gentle, program coordinator for USDA APHIS PPQ in Wyoming.
The agency’s surveys begin early in the spring, when grasshoppers first start to hatch.
“We start looking May 5 in the warmer parts of the state, and we don’t quit the nymphal surveys until July,” says Gentle. “Our goal is to find the populations before they reach the third instar.”
The five immature stages of grasshopper development are called instars.
“When we talk about control, we really have to understand our enemy. Being able to do treatments in nymphal instars is critical. It’s not cost effective to treat grasshoppers as adults,” says Gentle.
He adds that another advantage to finding young grasshoppers that early is that they won’t have had a chance to do much damage. “It saves a lot more forage, and they won’t be able to reproduce,” he says.
The second part of the surveys looks for adults, and that doesn’t usually start until mid-July.
“The goal is to identify areas where grasshoppers may be a problem the following year,” explains Gentle. “That’s what we’re looking at now – the adult survey to make predictions for 2011.”
The agency covers the state on a five-mile grid, doing collections to determine what species are in existence.
The USDA does grasshopper surveys by landowner request, and on the busier years it coordinates with local weed and pest districts.
“If you know you have a problem, and you want assistance, make sure you talk to them and get involved in the program ahead of time,” he suggests.
USDA’s technical assistance is provided at no cost to landowners.
“We’ll come out for density counts, species identification and instar classification to make sure the control chemical is applied at the right stage, and we can help determine some of the economic thresholds and work on treatment options,” says Gentle.
Of the treatment aspect of USDA, Gentle says landowners don’t have to use the USDA program for treatments, and there are some areas where a county will take care of treatments.
“When you sign up with the Weed and Pest, we’ll work with them to determine which areas make more sense for USDA treatments and which are best for Weed and Pest treatments,” says Gentle. “It usually boils down to the amount of federal land in a block, because of the cost share program.”
He says the cost share covers 100 percent on federal land, 50 percent on state land and 30 percent on private land.
And, USDA treatments can only be applied on rangeland, as they don’t have the authority for cropland, and they prefer large, contiguous blocks.
“We know the chance of reinfestation on small areas is too great. We want to make sure we get a big enough chunk that we’re not wasting money,” says Gentle.
USDA does offer a cropland protection program. Where federal land neighbors cropland the agency will spray areas of surrounding rangeland to protect the crops.
Another treatment is “hot spot” or “hatching bed” treatments, which are usually ground programs instead of aerial.
Gentle says the chemical Dimilin is by far the preferred choice for grasshopper control, and almost all of their programs are geared toward it. When applying chemicals, USDA incorporates the RAATs concept, which stands for Reduced Agent Area Treatments.
“Dimilin is labeled at two ounces per acre, but we know we can use three-quarters of an ounce,” says Gentle. “There are cost benefits to that, plus it lessens the environmental impacts and we still get great control.”
He adds the reduced area also includes treating every other swath, taking advantage of the grasshopper’s mobility.
“The year 2010 was a record in recent history for grasshopper control programs,” says Gentle. “We had 25 treatment planes in the state to get it done, and we did a really good job of reducing populations. I don’t expect to see a population resurgence in the areas treated last year, but there are a lot of areas that didn’t get treated where we expect high density numbers this year.”
As of late December, Gentle said the 2011 treatment programs are contingent on available funding.
“Until Congress gives us a budget we don’t know how much money we have for grasshopper control,” he notes.
Gentle says the program worked really well in 2010 because so many landowners signed up early, so they knew they had large blocks of land and what size they were.
“We did early bidding, which was critical in getting a low cost,” he adds. “In 2011, if we don’t have the signup done ahead of time we won’t be able to do those early contracts.”
He says some costs per acre in Montana were four times the cost of Wyoming programs because they didn’t contract early, and they didn’t have the large blocks of land. Wyoming’s cost to landowners in 2010 was $1.06 to $1.57 on rangeland per deeded acre.
“If you think you want to be involved, sign up now. If grasshoppers don’t show up, you don’t have to spray. If you’re not signed up and they do show up, there are too many hoops to jump through to get everybody on board late in the game,” he says. “When it’s all said and done we’ll figure out the exact cost and refund anything above and beyond.”
Gentle says “early” is by the end of March for the preliminary signup, and the end of April to finalize participants.     
For more information contact your local weed and pest district. Christy Martinez is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.