How to Manage Pests
UC Pest Management Guidelines
Scientific Names: Limonius spp. and others
(Reviewed 12/09, updated 12/09, pesticides updated 5/16)
In this Guideline:
Description of the Pests
Wireworms are shiny, slender, cylindrical, hard-bodied, yellow to brown larvae that can be found at all times of the year and in almost any kind of soil. The larval (or wireworm) stage of this insect may last several years. When fully developed, they vary in length from about 0.5 inch to 1.25 inches (12–31 mm), depending on the species. Adults of these larvae are known as click beetles. They can snap and flip their bodies into the air when turned upside down. These tan to black beetles vary from 0.25 inch (6 mm) to more than 1.0 inch (24 mm) in length, but the most common pest species are about 0.5 inch (12 mm) long.
Wireworm larvae injure crops by partially or completely devouring seeds in the soil, thus reducing plant stands. On plants, they can cut off small, underground stems and roots or bore into larger ones.
Preventive treatment may be warranted for crops planted in land that was previously pasture or planted to alfalfa, vineyards and possibly grains. Otherwise, good field sanitation and measures to ensure rapid seed germination aregenerally adequate for control of this pest.
Destroy plant residue from previous crops. Fallow fields for several weeks to allow organic matter to decompose. Seeds planted at depths greater than 1.5 inch (3.7 mm) take longer to germinate and are at greater risk for infestation. Do not plant into cold, moist soil.
Organically Acceptable Methods
Cultural controls are acceptable to use in an organically certified crop.
Monitoring and Treatment Decisions
If wireworms have been a serious problem in the past, a preventative treatment may be necessary. Preplant or seed treatments are far superior to any postemergence practice.
UC IPM Pest Management Guidelines: Cucurbits
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County
Acknowledgment for contributions to Insects and Mites:R. L. Coviello, UC Cooperative Extension, Fresno County
C. B. Fouche, UC Cooperative Extension, San Joaquin County
L. D. Godfrey, Entomology, UC Davis
J. B. LeBoeuf, AgiData Sensing, Inc., Fresno
M. Murray, UC Cooperative Extension, Colusa and Glenn counties
C. G. Summers, Entomology, UC Davis and Kearney Agricultural Center, Parlier