Canola-Cabbage seedpod weevil

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. 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)

  • bifenthrin (Bifenture EC Agricultural Insecticide, 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. a. i. per acre per season. Apply minimum 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 4.0 to 5.5 oz per acre. 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; lamda-cyhalothrin (Besiege, others) at 5 to 10 fl oz/A. Do not exceed a total of 28 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. PHI 21 days. Minimum interval between applications is 5 days. Apply in a minimum of 2 GPA water by air or 10 GPA by ground. If adjuvants are used, use only a 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 of water by ground.
  • gamma-cyhalothrin (Declare) at 0.77 to 1.54 fl oz/A or 0.0075 to 0.015 lb ai/A. PHI 7 days. Do not apply more than 0.045 lb ai per acre per season. When applying by air, apply a minimum of 2 gal water per acre.
  • lambda-cyhalothrin (Lamcap II) at 0.015 to 0.03 lb ai/A or 0.96 to 1.92 fl oz/A. Do not apply more than 0.09 lb ai (5.75 fl oz or 0.36 pints of product) per acre per year. Do not apply within 7 days of harvest.
  • 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 (Dyna-Shield Imidacloprid 5) at 10.24 to 25.6 fl oz per hundredweight of seed. In areas where foliar insects are in high numbers, the higher application rate is recommended. Do not graze for feed.