Pacific Northwest Insect Management Handbook

Canola-Cabbage seedpod weevil

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Image related to Canola-Cabbage seedpod weevil
Cabbage seedpod weevil
Ceutorhynchus assimilis Paykull
Immature
© Ken Gray Insect Image Collection
Image related to Canola-Cabbage seedpod weevil
Cabbage seedpod weevil
Ceutorhynchus assimilis Paykull
Adult female adult
© Ken Gray Insect Image Collection
Image related to Canola-Cabbage seedpod weevil
Cabbage seedpod weevil
Ceutorhynchus assimilis Paykull
Egg(s) showing damage
© Ken Gray Insect Image Collection

Ceutorhynchus asimilis

Pest description and crop damage The adult cabbage seedpod weevil (CSW) is ash-grey to black and approximately 4 mm (1/6 in) in length. Like all weevils, it has a snout that resembles an elephant's trunk. The larvae are white, C-shaped and legless and can be found only within the pod. Over-wintering adults enter canola near flowering and may feed on the flower buds, resulting in blasting. Summer-emerging adults can also cause injury by feeding directly on the green pods of later-planted fields. Pod-feeding by the larvae can cause up to 35% yield loss. They also vector alternaria leaf spot on the pods, which is common in Canada and moving into the Palouse region of the PNW. Control measures need to be taken if 20 or more adults are collected in ten 180-degree (side-to-side) sweeps.

Management-chemical control (Foliar Treatment)

  • azadirachtin (Azasol and other brands) spray at 6 oz (0.22 lb ai) in 50-gal water/A when pests first appear. Repeat application 5 to 7 days if required. Do not use it with oil. OMRI-listed for organic use.
  • Beauveria bassiana GHA (Mycotrol ESO, Mycotrol ES, BioCers WP, BotaniGard ES and BoteGHA ES) at 0.50 to 2 quart (0.014 to 0.054 lb ai/A) /100 gal of spray volume (unless BioCers WP 1.5 lb to 3 lb of product (0.2 to 0.6 lb ai/A) /100 gal of spray volume). Apply at 5- to 10-day intervals. High insect populations may require 2- to 5-day intervals. This product may be applied up to the day of harvest. REI 4 hr. Mycotrol ESO contains live spores of the naturally occurring fungus Beauveria bassiana Strain GHA. Spores are alive and may be harmed by storage at high temperatures or contact with water for more than 24 hr. OMRI-listed for organic use.
  • bifenthrin (Tundra EC, others) at 0.033 to 0.04 lb ai/A or 2.1 to 2.6 fl oz/A. Do not exceed 0.08 lb ai/A or 5.12 ounces of formulated product per acre per season. Apply a minimum of 10 gal/A by ground or 2 gal minimum by air. Do not apply within 35 days of harvest. Do not apply less than 14 days apart.
  • bifenthrin; zeta-cypermethrin (Hero Insecticide, others) at 0.04 to 0.053 lb ai/A. Do not exceed 5.5 oz per application. Do not apply more than 11 oz of product per season. Do not apply within 35 days of harvest. Do not make applications less than 14 days apart. Apply at a minimum of 10-gal water by ground and 2 gal by air.
  • chlorantraniliprole, lambda-cyhalothrin (Besiege) at 5.0 to 10.0 fl oz/A (0.049 to 0.098 lb ai/A). PHI 21 days. Do not exceed a total of 28.0 fl oz of Besiege or 0.09 lb ai of lambda-cyhalothrin-containing products or 0.2 lb ai of chlorantraniliprole-containing products per acre per year. Make no more than 4 applications per acre per crop. Only use non-ionic surfactant (NIS).
  • deltamethrin (Delta Gold) at 0.009 lb ai/A or 0.8 fl oz/A. Do not apply more than 1.5 fl oz of Delta Gold per acre on canola in one growing season. Allow 7 days between applications. Do not apply within 7 days of harvest. When applying by air, apply a minimum of 2 gal water per acre and 5-gal water by ground.
  • gamma-cyhalothrin (Declare) at 0.0075 to 0.015 lb ai/A or 0.77 to 1.54 fl oz/A. PHI 7 days. Minimum interval between applications 5 days. Do not apply more than 0.045 lb ai per acre per season. Do not apply within 7 days of harvest. When applying by air, apply a minimum of 2 gal water per acre.
  • lambda-cyhalothrin (LambdaStar Plus) at 0.015 to 0.03 lb ai/A or 0.96 to 1.92 fl oz/A. Do not apply within 7 days of harvest. Do not apply more than 0.09 lb ai (0.36 pint) per acre per year. Apply a minimum of 10 gal per acre for ground applications or 2 gal per acre for air applications.
  • zeta-cypermethrin (Mustang) at 4.3 fl oz/A or 0.05 lb ai/A. PHI 7 days. Do not apply more than 25.8 oz of product or 0.3 lb of active ingredient per acre per season. Do not make applications less than 7 days apart.

Management-chemical control (Seed Treatment)

  • imidacloprid (Attendant 600) at 10.24 to 25.6 fl oz per hundredweight of seed. In areas where foliar insects are in high numbers, a higher application rate is recommended. Do not graze within 45 days of planting.

Kaur, N. (Ed.). 2024 Pacific Northwest Insect Management Handbook.
© Oregon State University.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

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