Ravenous insects threaten hay crop, vegetable gardens
August 1, 2014
Steamboat Springs — Grasshopper counts at some locations across central Routt County have risen to levels where the insects are beginning to damage vegetable gardens and hay crops. But the number of ravenous hoppers is nothing like in summer 2002, when swarms of hoppers buzzed through city parks in Steamboat Springs and made it unpleasant to ride a bicycle along country roads.
"That was bad," USDA grasshopper inspector Carol Iverson said Thursday. "I remember they slept on the side of our house at night and were thick on the trunks of aspen trees."
Iverson's work for the USDA Animal and Plant Inspection Service takes her all across Northwest Colorado, where she tallies the numbers of grasshoppers per square yard.
CSU Extension Agent Todd Hagenbuch confirmed that when grasshopper counts exceed 10 to 20 per square yard, the insects can begin to damage crops. Grasshopper counts in summer 2002 were estimated to be as high as 120 to 180 per square yard.
Some people may perceive Routt County's grass hay to consist of just stems, Hagenbuch said, but it's really the long, slender leaves that wrap the stems of the plant that provide the nutrition. Grasshoppers can reduce hay yields greatly by eating those leaves.
Iverson has visited numerous areas this summer where grasshopper counts are well above the 10- to 20-per-square-yard threshold, but the most infested areas are widely spread and there have been only a couple of locations where this year, she has seen numbers to rival 2002.
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"I was out on Routt County Road 46 earlier in June, and I couldn't count them," she said. "You'd take a step in the field, and they would fly. I was estimating 80 to 120 (hoppers per square yard). I said, 'There can't be this many. This has to be something else.' They were covering the ground. I went back to the truck and got stronger glasses, and they were all (grasshopper) nymphs.”
She revisited the same site last week, and the hopper count was down to about 36, probably because of predation. But she also visited private property near Cullen's Corner and counted more than 50 hoppers per square yard.
Grasshoppers are not much of an issue in Hayden this summer, Iverson said, but California Park, just to the north, is "inundated." On the other hand, there are only moderate numbers of the insects in the Country Green subdivision just south of the Steamboat city limits.
But it's really summer 2015 that has Hagenbuch worried.
If the offspring of this year's abundant grasshopper population survive inclement weather next spring, they could compound the impact on crops and gardens.
The newly hatched hoppers, about the size of a pencil lead, are usually, but not always, susceptible in their first weeks to cold moisture. The grasshopper infestation of 2002 was preceded by three consecutive spring seasons that saw unusually mild weather.
"That's why I'm surprised at what happened this year," Hagenbuch said. "We didn't have a warm spring. Everybody is always learning how adaptable these little critters are. I'm concerned that the adult grasshoppers we're seeing right now are actively laying eggs, and depending on snow and temperatures next spring, there's a potential for even greater numbers."
For people living in neighborhoods with significant grasshopper counts this summer, whether they are a group of neighboring ranchers, a gardening club or members of a homeowners association, Hagenbuch urges them to begin planning for next summer in advance. He invites them to contact him at firstname.lastname@example.org this fall to put together an action plan to thwart the insects in summer 2015.