Identification

Wireworm larvae are slender, cylindrical insects. They are usually yellowish and resemble mealworms. They have six short legs close together near the head. Adults are click beetles; they do not weaken older plants.

Life Cycle

Common wireworm species require 3 to 4 years to complete their life cycle. Most of the time is spent in the larval stage, but all stages may be present at once during the growing season. The larvae move up and down in the soil in response to temperature and moisture. Mature larvae form a pupation cell of soil particles; they may pupate right away or remain in the cell over the winter, pupating in the spring. Adults that develop in the fall may also remain in pupation cells over the winter. In spring and summer, adults burrow to the surface. Both sexes are capable of flying to reach mates and egg-laying sites. Females burrow back into the soil to lay eggs.

Damage

Wireworm larvae injure sprouting seeds and seedlings by feeding on roots or shoots. They also bore into stems and other plant structures such as potato tubers. Damage is most common where soil has a high organic content.

Solutions

Prior to planting, flooding an area can help reduce populations. Reduce levels of organic matter. Carrots are especially attractive to wireworms. Plant a nearly fully grown carrot in the soil every 2 1/2 to 3 feet throughout the garden. Every 2 to 3 days pull up the carrots, remove the wireworms, and replace the carrots in the soil to trap more wireworms.