Grasshopper population increases
Numbers not expected to reach levels of infestation in 2002-03
April 23, 2009
Steamboat Springs — Routt County’s grasshopper numbers appear to be climbing, and the Colorado State University Extension office is urging people to watch for the insects.
A survey found three spots where grasshoppers were present in what is considered large numbers: at least 15 per square yard, Extension Agent CJ Mucklow said. The spots were west of Hayden near U.S. Highway 40, south of Steamboat Springs off Routt County Road 14 and near the Twentymile mine.
The area near C.R. 14 showed the highest concentration: 44 grasshoppers per square yard. Nine to 14 grasshoppers per square yard were reported at six other spots in Routt County.
“I did not think we’d ever have grasshoppers again,” Mucklow said.
When 15 grasshoppers are found in a square yard, treatment might be warranted, he said. Mucklow asked people who start noticing grasshoppers in late May or early June to call the Extension office at 879-0825.
“We’re telling people early, because the most effective treatment is when they’re young,” he said.
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The county wrestled with the problem in 2002 and 2003. During that period, surveyors found as many as 100 to 200 grasshoppers per square yard, according to a Steamboat Pilot & Today story from June 6, 2005.
The Animal and Plant Health Inspection Service, part of the U.S. Department of Agriculture, sends people out to count grasshoppers. The adult grasshoppers found in 2008 are indicative of what will happen in 2009 because they’ll lay eggs, Mucklow said.
Data collected in 2007 showed no spots with more than 15 grasshoppers per square yard, Mucklow said.
A dry, warm year provided good conditions for grasshopper survival, he said. After they hatch, the insects are vulnerable to wet weather. If they can’t dry off daily, grasshoppers are more susceptible to disease, Mucklow said. A wet spring could decrease numbers.
Grasshoppers eat 20 percent to 25 percent of prairie vegetation in the West, said Alex Latchininsky. He is an associate professor and extension entomologist for the Department of Renewable Resources at the University of Wyoming in Laramie.
“They are in competition with livestock and with all wild animals that are in all the rangeland,” Latchininsky said. “And this is just the direct impact. : The only way to deal with grasshoppers is to use chemical pesticides, at this point, and so we are putting a lot of chemicals into the ecological system.”
Colorado’s largest grasshopper populations are expected to be in the eastern and southwestern regions. Mucklow said that was typical. High numbers in Routt County are unusual, he said.
The county’s grasshopper infestation began in 2002, according to the 2005 newspaper story. Grasshoppers were still around in high numbers in 2003 but began to taper off in 2004. In 2003, the Extension office sprayed growth-inhibiting insecticide on about 28,000 rural acres, the story reported.
The grasshoppers are native, Latchininsky said.
“They are not invasive, contrary to some weed species, and in Colorado, in Northern Colorado, there are probably about 100 grasshopper species,” he said. “So they are really interesting insects. They are important for the ecological food chain, good fish bait. : We try not to exterminate them but just lower their densities.”
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