This is the Big Eyed Click Beetle, of the family Elateridae.
Handsome. Unfortunately its larvae, wireworms, can be devastating to a potato crop and root crops like carrots. Following the carbon dioxide released by the target plant it bores into them. They’re very tough to get rid of, pesticide resistant, and provide a starter hole for further damage by slugs.
They also harm cereal crops, like corn and wheat.
I’ve never had a problem before, but since I saw this adult, I expect to see wireworms this year when I harvest the potatoes. I’ve found a number of suggestions for reducing the damage/preventing infestations, some of which it’s too late for this season, since I’ve already planted my ‘taters, but I will remember them for next year.
- Try not to plant potatoes where you had them last year, or where you recently had grass.
- Till deeply and before planting and leave the bed for the wild birds to clean out the worms for a period of time. Ducks or chickens would do a good job, too.
- Plant in loose, friable soil, as opposed to heavy clay.
- Plant several cut potatoes prior to planting time to act as a “trap” crop. Go back in and remove the infested trap potatoes, then plant your actual crop.
- Plant only whole potatoes as opposed to cut up pieces for your real crop.
- Put coffee grounds in the trench, then plant potatoes.
- Alternate dry and wet conditions in the soil to make conditions unfavorable for the worms.
If you’ve had experiences with wireworms or found good controls, please add them in the comments.