PEST ALERT!! Western Corn Rootworm in B.C. (Jan 2017)

Western Corn Rootworm (WCRW), Diabrotica virgifera, Family: Chrysomelidae, a major corn pest, was confirmed in the central and eastern Fraser Valley in August 2016. Surveying in August and September revealed varying levels of infestation in fields, in both silage corn and sweet corn. WCRW has also been confirmed in a dahlia crop adjacent to corn fields.

western corn root worm adult beetle

Life cycle: One generation per year, eggs laid in established corn in late summer in soil cracks. Eggs overwinter, hatch in spring, and larvae are attracted to and feed on corn roots of planted corn fields for 1 month. Larvae pupate in soil, and adults emerge in July. Adults feed on corn foliage and pollen, and mate. Beetles are active fliers and will feed on many plants. Females feed for two weeks, and then lay eggs in corn fields. Both males and females live for about 1 month.

Damage:

  • Root pruning by larvae, decreasing corn plant growth and causing full or partial lodging
  • Feeding on silks, affecting cob fill, and cob contamination
  • Feeding on flowers (i.e. dahlia), affecting marketability If you see this pest in your corn or flowers, management may be necessary.

Management includes: Crop rotation out of corn every 2-4 years, use of seed treatments or in-furrow sprays at planting, foliar spray for adults in July-August.

If you have questions, contact: British Columbia Ministry of Agriculture
Abbotsford Ph: 604-556-3001
Kelowna Ph: 250-861-7681

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