It should come as no surprise to insect geeks that the ash-grey insect above with a rather distracting snout is a weevil. More specifically, it’s a cabbage seedpod weevil (Ceutorhynchus obstrictus), an insect pest that has been infecting canola crops (and other Brassicaceae species) in Alberta since the mid-1990s, and it has since moved across the southern portion of the province and into Saskatchewan.
Adult cabbage seedpod
weevils will often drop to
the ground and play dead
According to Alberta Agriculture and Forestry, thresholds are reached when an average of 3 to 4 adults are collected per 180° degree sweep sample at 10 to 20% flowering.
In this video, Scott Meers, insect management specialist with Alberta Agriculture and Forestry talks about cabbage seedpod weevil populations in Alberta and Saskatchewan, what could be confused with feeding symptoms and how many weevils constitutes a threshold for chemical control.
For more information, check out Alberta Agriculture and Forestry’s video on proper sweep techniques for cabbage seedpod weevil.