Wireworms

Wireworms are found in the soil where they feed on the roots of various cereals. Damage is done by the larval stage, which is a yellowish brown, thin worm that has a shiny, tough skin.

Wireworms feed on roots of emerging plants, killing the seedlings and reducing the stand. As plants mature, wireworms may girdle the stem, causing white heads. In appearance, this damage is similar to that caused by common root rot, take-all, or wheat stem maggot. Be sure to dig around the plant and look for wireworm larvae to confirm that they are the cause of injury.

In fields known to contain wireworm larvae, fallow during summer with frequent tillage (springtooth or disk). Damage from wireworm infestations to the crop when it is in the seedling stage can sometimes be reduced by replanting, if replanting occurs before existing plants begin to tiller. Rotate to nonhost crops if possible. Contact your county farm advisor for information regarding nonhosts. Do not plant a susceptible host crop following a cereal crop that has had a heavy infestation of wireworm without fallowing/tilling or applying a pesticide.

Wireworm infestations are difficult to detect prior to visible plant injury. They are most likely to be found following a long-term legume crop or natural or temporary pasture.

Chemical controls are ineffective or impossible to apply to wireworms attacking a standing crop. If used, chemicals must be applied as preplant or seed treatments. If an insecticide is to be used before planting a cereal crop or rotational crop, check the label for plantback restrictions or possible residue problems.