How to Manage Pests

UC Pest Management Guidelines



Scientific names: Limonius spp. and others

(Reviewed 1/06, updated 8/08, corrected 3/19)

In this Guideline:


Wireworms are the soil-dwelling larvae of click beetles. They resemble mealworms and are slender, elongate, yellowish to brown with smooth, tough skin. The body is usually cylindrical, but flat on the lower side. There are six short legs close together near the head, and the tip of the abdomen bears a flattened plate with a pair of short hooks.

Wireworms may remain in the soil as larvae from 1 to 3 or more years, depending upon the species and the food supply.


Wireworms feed on seeds and root portions of a wide variety of plants. In corn they can destroy germinating seeds and tiny seedlings. Often the wireworm will be found near the damaged or missing seed or plant. Wireworms will also attack young plants, resulting in weakened plants or a reduced stand. Damage is most likely to occur where corn is planted into a field formerly in pasture or weedy alfalfa.


If wireworms have been a serious problem in the past, a preventive seed treatment or a treatment at planting may be necessary.

Common name Amount/Acre** R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, information related to natural enemies and honey bees and environmental impact. Not all registered pesticides are listed. Always read label of product being used.
  (Cruiser 5FS)   12 NA
  COMMENTS: Use allowed under a supplemental label. Do not apply other neonicotinoid (Group 4A) insecticides within 45 days of planting seed treated with this product. May provide only partial control under high population pressure.
  (Poncho)   0 NA
  COMMENTS: A seed treatment. Do not apply other neonicotinoid (Group 4A) insecticides within 45 days of planting seed treated with this product.
** Mix with sufficient water to obtain full coverage.
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
1 Modes of action are important in preventing the development of resistance to pesticides. Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode of action is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at
NA Not applicable.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Corn
UC ANR Publication 3443

Insects and Mites

L. D. Godfrey, Entomology, UC Davis
S. D. Wright, UC Cooperative Extension, Tulare County
C. G. Summers, Kearney Agricultural Center, Parlier
C. A. Frate, UC Cooperative Extension, Tulare County
Acknowledgement for contributions to Insect and Mites:
M. J. Jimenez, UC Cooperative Extension, Tulare County

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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