Wireworms
Hard, shiny, yellow to orange-brown grubs that look like short lengths of wire and live in the soil for two or three years. They bore narrow round holes into potatoes, sweet potatoes and carrots, and eat sprouting seeds before they ever come up.
Pest checklist
Four things to look for. If most of them match what you are holding, you are in the right place.
What gets rid of them
Gentlest option first. For most backyard cases the first one is enough, so try these in order and stop as soon as it works. If you do spray something, the product label tells you how — please read the notice further down.
1Bait and pull them
Bury chunks of potato or whole carrots a few inches deep every few feet, dig them up every two or three days, and destroy the grubs clinging to them.
Try this first2Wait out new ground
Give newly broken sod a year or two of cultivated crops that are not root crops before you put potatoes or carrots there.
3Cultivate before planting
Turn the bed over a few times in spring; it exposes grubs to birds and dries out part of the population.
garden broadfork4Harvest on time
Dig potatoes and sweet potatoes as soon as they are ready, because the longer they sit in the ground the more holes they collect.
As an Amazon Associate, Story Thyme Farms earns from qualifying purchases, at no cost to you. It never changes what we recommend.
Which plants get wireworms
Every plant we cover that gets wireworms, grouped by type — tap any one to open its page. A note beside a plant came from that plant’s own entry, because the same pest can be a minor nuisance on one plant and a serious problem on another. Plenty of plants we do not cover get it too.
biennial1
bulb1
When to treat
This one is decided before you plant. There is no rescue spray for a home garden, so if the bed was sod recently, keep potatoes, sweet potatoes and carrots out of it for a couple of seasons.
Timing only — the label is the law
This page tells you when to watch for wireworms and when treating is worth considering. It is not a recommendation to apply any particular product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.
- Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
- Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
- Confirm the product is registered for your crop in your state. This page groups many different crops together, and a product legal on one of them is not legal on all of them — state registrations differ too. Your state pesticide agency or local extension office can confirm both.
- Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.
Other problems on the same plants
If a plant gets wireworms, these are the problems it most often gets as well, so they are worth checking for while you are out there. They tend to appear together; one does not cause another.