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.