Wireworms

What are Wireworms

Wireworms look like short (½ inch) reddish brown worms, but they are actually the larval stage of the click beetle. There are several species of wireworms, distributed throughout most of the world. Wireworms are very common in most types of soil and can be found year round.

Both wireworms and the adult click beetle can overwinter in the soil and in some species, so can their eggs. The adults first emerge around May or June and live for several months, throughout the summer. The female lays her eggs in the soil often near roots or grasses. The eggs hatch into larval about 2 weeks later and as soon as that happens, they begin looking for food. Larva can take 2 to 6 years to fully mature, eating the whole time.

Damage from Wireworms

Wireworms feed on a wide range of plants. Commercially, they are a big pest of corn and potatoes, but in home gardens they will feast on what’s available. If they feed on the roots, the plants will be slow to grow, with poor vigor and low yields. Wireworms may burrow right into root crops, like potatoes, deforming the tuber and making holes that invite disease.

Controlling Wireworms

Since wireworms are so common, they are extremely hard to control. However, if you suspect wireworms are present, here are a few techniques you can try to limit their destructiveness.

1. Cultivate your soil in May/June, when they hatch, to expose them to hungry birds.

2. Use chunks of potato as a decoy trap. Skewer a piece of raw potato and bury it near the problem area, with the skewer above ground marking its spot. Dig after about 1 week and check for the presence of wireworms. Dispose of the potato piece, wireworms and all.

3. Remove and destroy infected crops after harvesting, to limit overwintering.

4. The nematode Heterorhabditis megadis attacks wirewomrs. Heterorhabditis megadis needs to be applied to the soil as the wireworms are hatching and reapplied each year.