How to Manage Pests
UC Pest Management Guidelines
Scientific Names: Limonius spp. and others
In this Guideline:
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
are generally 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.
Cultural controls are acceptable to use in an organically certified
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
|The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, pesticide registrations, information related to natural enemies and honey bees, and environmental impact. Not all
registered pesticides are listed. Always read the label of the product being used.
||7–10.5 fl oz
||MODE OF ACTION GROUP NUMBER1: 4A
||COMMENTS: Apply at planting or transplanting and incorporate into root zone.
||COMMENTS: Labeled for use on melons
and watermelons only. Broadcast just before planting and immediately work into the soil 4–8 inches.
||COMMENTS: Apply as a band treatment before planting. Fumigants
such as metam sodium are a source of volatile organic compounds (VOCs) but
are minimally reactive with other air contaminants that form ozone. Fumigate
only as a last resort when other management strategies have not been successful or are not available.
UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County
J. J. Stapleton, UC IPM Program, Kearney Agricultultural Center, Parlier
C. S. Stoddard, UC Cooperative Extension, Merced & Madera counties
Acknowledgment for contributions to Insects and Mites:
R. L. Coviello, UC Cooperative Extension, Fresno County
L. D. Godfrey, Entomology, UC Davis
C. B. Fouche, UC Cooperative Extension, San Joaquin County
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
J. B. LeBoeuf, AgriData Sensing, Inc., Fresno
M. Murray, UC Cooperative Extension, Colusa/Glenn counties
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