How to Manage Pests

UC Pest Management Guidelines

Tomato

Wireworms

Scientific name: Sugarbeet wireworm Limonius californicus and other Limonius spp.

(Reviewed 12/13, updated 12/13)

In this Guideline:


Description of the Pests

Wireworms are shiny, slender, cylindrical, hard-bodied, wirelike, yellow-to-brown larvae found at all times of the year and in almost any kind of soil; the larval (or wireworm) stage of this beetle may last several years. Adults of these larvae are known as click beetles.

Damage

Wireworm larvae injure crops by devouring seeds in the soil, thus preventing seedlings from emerging; by cutting off small, underground stems and roots; and by boring into larger stems and roots of transplants.

Management

The presence of wireworm larvae can be monitored by burying carrot or potato pieces on the surface to 3 inches deep into the soil at several locations throughout the field during seeding. Check weekly for holes in the carrot or potato from wireworm feeding. No thresholds have been developed.

Common name Amount per acre** R.E.I.‡ P.H.I.‡
(example trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
The following materials are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
PREPLANT
 
A. DIAZINON*
  (Diazinon AG500) 3–4 qt 24 NA
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: A soil application; may also be applied via chemigation. Apply immediately after transplanting when conditions suggest wireworms could be a problem.
 
AT PLANTING, TRANSPLANTING, AND POSTPLANT
 
A. CLOTHIANIDIN
  (Belay) 9–12 fl oz 12 NA
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: A soil application at planting or transplanting.
 
B. IMIDACLOPRID
  (Admire Pro) 7–10.5 fl oz 12 21
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: A soil application; may also be applied via chemigation. Apply immediately after transplanting when conditions suggest wireworms could be a problem.
 
C. ACETAMIPRID
  (Assail) 0.6–1.7 fl oz 12 7
  MODE-OF-ACTION GROUP NUMBER1: 4A
 
** See label for dilution rates.
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 until harvest can take place. In some cases the R.E.I. exceeds the P.H.I. The longer of these two intervals is the minimum time that must elapse before harvest may take place.
* Permit required from county agricultural commissioner for purchase or use.
NA Not applicable.
1 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 to help prevent the development of resistance. 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 group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Tomato
UC ANR Publication 3470

Insects and Mites

E. T. Natwick, UC Cooperative Extension, Imperial County
C. S. Stoddard, UC Cooperative Extension, Merced and Madera counties
F. G. Zalom, Entomology, UC Davis
J. T. Trumble, Entomology, UC Riverside
G. Miyao, UC Cooperative Extension, Solano and Yolo counties
J. J. Stapleton, UC IPM Program and Kearney Agricultural Center, Parlier (false chinch bug)
Acknowledgments for contributions to Insects and Mites:
C. G. Summers, Entomology, UC Davis and Kearney Agricultural Center, Parlier
C. F. Fouche, UC Cooperative Extension, San Joaquin County
N. C. Toscano, Entomology, UC Riverside

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