Grasshopper
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Grasshoppers have invaded Baker Valley.

Oregon - A grasshopper plague spawned in drought-parched rangeland where the voracious insects laid their eggs last summer, is spreading to wheat, hay and potato fields, where crop damage could be devastating.

"The USDA's threshold for economic damage is eight grasshoppers per square yard. In some heavily infested areas, we've had counts of 100 to 120, and possibly up to 140 grasshoppers per square yard," said Cory Parsons, Oregon State University Extension agent for Baker County.

"They are probably as close to an epidemic as they can be in Baker Valley," Parsons said. "When you get into them, you know, because the ground is just crawling with grasshoppers."

Three weeks ago the grasshopper infestation was limited to pockets scattered around the county, primarily on rangeland, but Parsons said the situation has taken a dramatic turn for the worse.

"We're finding grasshoppers from the north end of the Baker Valley off Ladd Canyon all the way to Huntington, and from Medical Springs, Sparta and Keating to the Burnt River, Unity and Hereford," Parsons said.

"Eagle and Pine Valley, around Halfway and Richland, the Sumpter Valley and Whitney Valley are the only places we have no grasshopper populations," Parsons said.

When grasshoppers are small they typically remain in the dryer rangeland areas where they hatch from eggs, but once they mature and sprout wings, Parsons said "they will move into wheat, alfalfa and potato fields and do some substantial damage."

That scenario appears to be coming to pass, Parsons said, based on phone calls to the Extension Service and aerial pesticide applicators from concerned farmers and ranchers across Baker County.

"With the rangeland drying up, the guys out cutting hay are finding grasshoppers coming into hay ground," Parsons said.

The infestation extends far beyond Baker County to an estimated 1 million acres across Northeastern Oregon, according to reports from the Oregon Department of Agriculture, which dispatched a team to help locate and map areas with the heaviest grasshopper populations.

Aerial pesticide spraying initiated this week is designed to kill flying adult grasshoppers after spring applications of biological control products failed to knock down the grasshopper population at the egg or nymph stage, Parsons said.

"We sprayed yesterday, we sprayed today, and we'll spray again tomorrow," said Parsons, adding that he's spent the past 18 days working on grasshopper control efforts with landowners, pesticide applicators and representatives from the ODA.

"Once grasshoppers reach the adult stage, sprout wings and start flying around, the only thing you can do in heavily infested areas is spray pesticides and hope you can bring the population under control before they do too much crop damage," Parsons said.

The Bureau of Land Management has applied for federal dollars to spray grasshoppers on federal land, but Parsons said there's no state or federal funding to help offset the cost of spraying pesticides to combat the pests on private land, so the burden falls largely to farmers, ranchers and other landowners.

Faced with a choice between spending thousands of dollars for pesticide applications or standing by while the pests devour their crops, Parsons said some growers may be tempted to ride it out, but that choice could have devastating effects on their crops, as well as crops on neighboring farms and ranches.

He warned landowners who do nothing and hope for the best that "once grasshoppers finish devouring vegetation on your land, they will move to your neighbors."

Several pesticide products are available for use on grasshoppers. However, Parsons said the product Mustang MX is one of the most effective and the most widely used product in this area.

While the biological growth regulator Dimilin 2L used to kill young grasshoppers at the molting stage is very effective and highly selective, killing only the insect group that includes things like grasshoppers, mormon crickets and the praying mantis, Parsons said use of broad- spectrum pesticides like Mustang MX is the only viable option for killing adult grasshoppers.

"Once we get large populations of winged grasshoppers, Dimilin won't work," he said.

The downside of applying broad-spectrum pesticides is that they can also kill off beneficial insects ranging from lady bugs to honey bees, Parsons said.

In an effort to protect the region's already declining honeybee population, Parsons is encouraging landowners and pesticide applicators to notify owners of beehives to move their hives before spraying to control grasshoppers.

Mustang MX and some of the others effective against adult grasshoppers are restricted-use pesticides that can only be applied by a licensed pesticide applicator, either with ground spraying equipment or by aerial application with a crop-duster type of airplane or helicopter. However, Parsons said Mustang MX is relatively safe to use.

It can be sprayed right over a pasture full of cattle without harming the cattle, and there's no delay for reentering a field after it's been treated with Mustang MX and similar pesticide products.

In addition to the goal of minimizing crop damage, Parsons said the pesticide spraying program is designed to reduce the adult population before it lays eggs, in hopes of preventing an even larger grasshopper explosion next year.