Any hopes that recent wet weather might wash out the memories of last summer's grasshopper plague already have been erased at Larry and Mary Kay Monger's Hightide Ranch.
Already this spring, Mary Kay Monger has seen grasshoppers covering her family's pastures at the foot of Sleeping Giant Mountain. After encountering millions of them last summer, she decided to take proactive steps this year by meeting with neighbors as early as February to discuss how to handle the problem.
"I said to myself, 'I'm not going through another summer like that,'" Monger said. "I'll do whatever I can to get rid of them."
She was one of 20 or so people who volunteered to count grasshoppers and determine their concentration. Checking her own land first this spring, she contacted Colorado State University Cooperative Extension Agent C.J. Mucklow to report that indeed, they were back.
Mucklow visited Mongers' ranch Thursday morning and counted 360 of the tiny pests in one square yard of dry land. That number is nine times the threshold classified as a severe infestation, clearly justifying the use of insecticides, Mucklow said.
Last year, a grasshopper infestation devastated grazing land, crops and lawns last summer. This year, the potential for infestation is "as bad as last year, if not worse," Mucklow said.
Most of the grasshoppers are "clearwinged," classified Camnula pellucida, Mucklow found, although several other speicies are present. They thrive in hot and dry conditions where their eggs can hatch successfully, so last year's drought was an ideal environment for them.
The tiny grasshoppers showing up now are the offspring of last year's swarm, and the unseasonably warm spring is once again welcoming them, said Dr. Carl Bock, a professor of grassland ecology at the University of Colorado at Boulder.
If allowed to fully mature, it would only take 20 of the infant grasshoppers that Mucklow counted at 360 in a square yard on the Mongers' property to consume all the vegetation in the area they cover, according to the Wyoming Geographic Information Science Center.
To combat the grasshoppers, Mucklow has chosen to use a growth-inhibiting insecticide called diflubenzuron, or more commonly known as Dimilin. Dimilin is considered environmentally sound because of its minimal effects on non-target animals.
The U.S. Department of Agriculture encourages protecting nontarget organisms whenever possible because some nontargets work naturally to keep pest populations in balance.
Dimilin's growth-inhibiting capability makes it different from most insecticides. It prevents the formation of chitin, the substance that makes up a grasshopper's exoskeleton, which can kill the insect when it attempts to molt. Because the grasshoppers here are in the larval stage, Dimilin will prevent their outer casing from maturing with their internal structure, causing them to rupture.
John Worden, a homeowner on Routt County Road 44, isn't taking any chances.
Last year, his grasshopper infestation was so "horrific," his dogs wouldn't go outside, Worden said. The swarm "of Biblical proportions" was so thick that his two boys took turns shooting the grasshoppers with BB guns and were successful in bagging several of them, Worden said. Almost all of the grass on his 40 acres was eaten "to bare dirt."
"The only thing they didn't eat was the weeds," Worden said. "If we could educate them to eat the weeds instead, it would be great."
After seeing thousands of the insects return this year, Worden contacted the CSU Cooperative Extension on Thursday to have his land assessed. Mucklow found Worden's land could justifiably be sprayed with Dimilin.
"It's like little black clouds popping up every step you take," Worden said.
Worden said he wished he had the know-how to make chocolate grasshoppers.
"It's a shame we can't make money off of this," Worden said with a chuckle. "We may be sitting on a gold mine."
Mucklow said in order to spray Dimilin, a high concentration of grasshoppers -- at least 40 per square yard -- must be present in an area of at least 100 acres. Spraying high concentrations of grasshoppers can greatly reduce the overall of impact on vegetation, Mucklow said.
To reduce cost, Dimilin can be sprayed in strips to cover as little as 50 percent of an infested area and still be effective. When mixed with canola oil, the grasshoppers are attracted to it and come in contact with it.
Scott Flower, managing partner of Wolf Run Ranch off Twentymile Road, said he has also been in contact with CSU Cooperative Extension and asked for his land to be sprayed with Dimilin.
The grasshoppers are concentrated in the sunny south-facing slopes on the 2,500-acre ranch, just as they were last year, but in smaller numbers. Last year, Flower spent nearly $3,000 on bait formulas and crop dusting with the insecticide Malathion in attempts to eradicate the insects.
Mucklow said he began planning similar aerial sprays earlier in the week, but has not found large enough concentrations to justify it and put the spraying on hold.
The rural community working together will be key for persevering through another infestation, Mucklow said.
"I don't want to claim or pretend that we're going to stop this infestation," Mucklow said. "This is a natural thing that is too big for us to handle alone. Mother Nature should help with cool weather this weekend. One way or another, it should eventually clear up on its own."
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