HPIPM:Wireworms FC
Author: Frank B. Peairs[1]
Identification (and life cycle/seasonal history)
Wireworms are the larval stage of a family of beetles (Elateridae) commonly called "click beetles." There are several species of wireworm whose life cycle may require one or more years per generation. The insects usually overwinter in the adult stage. Adults are brownish or even blackish in color, elongate and tapering toward each end but more so toward the rear. The earliest stages of larvae are very small and white, later stages have a characteristic hard shell appearance and a yellow brown color. Mature larvae range from ½ to one inch in length, depending on the species.
Females deposit eggs in the soil among grass roots. When the eggs hatch the larvae feed on the roots of corn and other grasses. The larvae mature in from two to five years. Fully developed larvae form pupation chambers in the soil and pupate. Adults emerge from the pupae and remain in the soil until the following spring.
Plant Response and Damage
Wireworm populations in corn are most severe in corn fields following sod or fields having a prolonged grassy weed problem. Wireworms feed on germinating corn seeds and early corn seedlings, and may bore into stalks at the soil level. There may be significant stand loss if there is an abundant population in the field.
Management Approaches
Chemical Control
Wireworms should not be a concern if a soil insecticide is used for control of corn rootworms. A corn seed protectant should be used if a soil insecticide is not used (see the rootworm chapter for details). Seed protectants are available with active ingredients including clothianidin (Poncho), imidacloprid (several products), permethrin (generic, several products), and thiamethoxam (Cruiser).
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.
