How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PESTS

Wireworms are beetle larva that are found in soil where they feed on roots. They are yellowish brown, thin worms that have a shiny, tough skin. Adults of the wireworms are click beetles, so named because their elongated bodies are capable of producing a clicking sound. Only the larval stage causes damage.

DAMAGE

Wireworms feed on roots of emerging plants, killing the seedlings and reducing the stand. As plants mature, wireworms may girdle the stem. Be sure to dig around the plant and look for wireworm larvae to confirm that they are the cause of injury.

MANAGEMENT

Cultural Control
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. Rotate to nonhost crops if possible; contact your county farm advisor for information regarding nonhosts. Do not plant a susceptible host crop following a crop that has had a heavy infestation of wireworm without fallowing/tilling or applying a pesticide.

Monitoring and Treatment Decisions
Wireworm infestations are difficult to detect before visible plant injury occurs. They are most likely to be found in a sugarbeet field when sugarbeet follows 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.

Common name		Amount/Acre
(trade name)
When choosing a pesticide, consider information relating to water quality and impact on natural enemies and bees.
A.	DIAZINON* 14G	21-28 lb
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Broadcast and incorporate.
	...OR...
	DIAZINON* 50W	6-8 lb
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Broadcast and work into soil 4-8 inches immediately. Avoid drift and tailwater runoff into surface waters.
	...OR...
	DIAZINON* AG500	3-4 qt
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Immediately work into top 4-8 inches of soil. Avoid drift and tailwater runoff into surface waters.
*	Permit required from county agricultural commissioner for purchase or use.
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 http://www.irac-online.org/.

PUBLICATION

UC IPM Pest Management Guidelines: Sugarbeet
UC ANR Publication 3469
Insects and Mites
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
D. R. Haviland, UC IPM Program, Kern Co.
L. D. Godfrey, Entomology, UC Davis

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