| Life Cycle: | The adult wireworm is a dark brown beetle 1-2 cm in length. It is also known as the 'click beetle' because it has a physiological mechanism that allows it to turn itself over when it gets flipped over on its back. This produces an audible click as the beetle is flipped over. The wireworm overwinters in Atlantic Canada as a mature click beetle underneath the soil surface. Adults emerge in the spring and feed on the nectar from flowers. They do no agricultural damage. In June they begin laying eggs. The eggs are laid singly or in clusters and are generally laid in sod, clover or cereal fields. The eggs hatch in approximately three weeks; however, because egg laying takes place over time, the wireworm can be found in various stages throughout the summer months. The larvae will feed on the roots of plants in the field where they hatched. For this reason, vegetable crops that are rotated into a field infested with wireworms will be vulnerable. Wireworms have a long life cycle - up to five years. The larva will rise and descend in the soil depending on moisture levels and temperature. When pupation eventually does takes place, it tends to occur from late July to mid August. The adult will remain in the pupa until mature. |
| Host: | Wireworms prefer sod as well as barley, oats, clover and wheat; however, wireworms will feed on horticultural crops such as potatoes, beans, carrots, corn, strawberries, lettuce and melons. |
| Bio Region: | Throughout North America. |
| Damage: | The wireworm feeds on the roots and seeds of host plants. Damage in fields that were directly seeded usually takes the form of patchy germination. Damage to the root systems of transplants can result in stunted growth and reduced yield and quality. Crops with large tubers such as potatoes, rutabagas and carrots may have pits or bore holes in them. |
| Management: | Most of the life cycle of the wireworm is spent below the soil surface so managing the population can be difficult. Crop rotation is a valuable component of the management strategy, particularly if the presence of wireworms has been confirmed. Wireworms are within 15 cm of the surface in the spring after soil temperatures have reached 10C. This means that spring tillage not only aids in detecting an infestation by exposing larvae to their predators, it also disrupts the larvae when they are most vulnerable. If wireworm larvae are found, it may be adviseable to change the rotation if a susceptible crop was supposed to be planted in the potentially infested field. In their place crops that wireworms avoid should be planted. These include alfalfa and buckwheat. Fallowing the suspect field the year prior to planting susceptible crops will help keep populations down. This works by depriving the wireworm of food. It also exposes the soil to potential erosion. |
| Controls: | There are no chemical or biological controls that are allowed in organic systems which target wireworms. |
