The West’s Insect Issue
In large swaths of Oregon, Montana, and Wyoming, as well as some areas of Idaho, Arizona, Colorado, Texas, and Nebraska, the native insects are appearing on the heels of a dry planting season. Grasshoppers and drought go together like PB&J, so the insects are having a hayday.
Not seen by some growers since the mid-1980s, grasshoppers attack rangeland and crop fields. They chew through tender plants, leaves, and grain heads, and are a competitor for livestock forage on public lands, where ranchers have no easy back up plans for the damaged food supply.
No small issue: Populations of 14 grasshoppers per square yard – totaling the weight of a sheep – become a problem. They can eat their bodyweight in forage each day, leading to a $900M impact from a typical infestation. This year, populations are reaching 50-60 grasshoppers per square yard.
Taking care of business: This week, the USDA began spraying diflubenzuron in hard-hit Montana to kill nymphs. Conservationists are concerned about impacts to other insects in the treated area. But officials say their skip-a-swath approach protects slower moving insects while targeting the far-traveling grasshoppers.
Where this goes: Without killing nymphs, the outbreak will peak in roughly two months when the 2-3 inch-long insects will be able to out-eat cattle. They’ll die out when they run out of forage – and likely after they’ve laid next year’s eggs.