Shortage of broad-spectrum pesticides a problem for growers
By DAN WHEAT
The Northwest may experience a severe outbreak of grasshoppers this summer.
Any green crops and grasses next to rangeland near Othello, Yakima and the Tri-Cities, in southern Idaho and central and southern parts of Eastern Oregon are most susceptible, said Richard Zack, associate professor of entomology at Washington State University in Pullman, Wash.
A WSU press release and the Associated Press reported the outbreak may be the worst in 30 years, but Zack said that's the forecast for the Dakotas, not the Northwest. No one knows how severe it will be here, but it shouldn't be as bad as in the Dakotas, he said.
USDA surveys last fall showed a dramatic increase in the number of grasshopper eggs in the Dakotas, Montana, Nebraska and Wyoming, traditional areas of large grasshopper populations because of huge amounts of rangeland, Zack said.
A mild winter and normal spring have made for good egg development, he said.
Any outbreaks will occur in July and August, when rangelands dry up and grasshoppers move out looking for food, he said.
"We may see some clouds of grasshoppers here but nothing like back there (in the Dakotas)," Zack said.
Grasshoppers wiped out about 7,000 acres of grassland in Malheur County in southeastern Oregon last summer and that can be expected again this year, he said.
Grasshoppers can fly up to 50 miles a day looking for food, he said.
There also could be outbreaks of the Mormon cricket, an insect that does not fly but can be more devastating because it eats most of a plant, not just leaves, he said.
Growers who have had problems or are next to rangelands should be vigilant in July and August, he said.
Elizabeth Beers, entomologist at the WSU Tree Fruit Research and Extension Center in Wenatchee, said grasshoppers and Mormon crickets can be just as devastating to vineyards and tree fruit foliage, particularly young trees, as to other crops.
Apples would sunburn without leaves and would not get their sugar from photosynthesis from the leaves, she said.
"We used to have enough broad-spectrum pesticides that we didn't have to worry about some of these types of pests, but now we don't use as many broad-spectrum pesticides, so it could be more of a problem," she said.
Grasshoppers devastated parts of the West and caused famines as late as the early 1900s, she said.