Before I jump into the pest alert, I want to welcome John Fluttert, the new Edible Bean and Oilseed Specialist on the Field Crop Team based at Ridgetown. He is getting his feet wet pretty quickly, managing calls about cabbage seedpod weevil (CSPW) infestations in winter canola fields in Essex and Chatham Kent. Despite the “harsh winter”, the snow cover has enabled beetle/weevil pests to overwinter well. These warm spring temps have also helped their activity align well to early bloom stages of winter canola. High risk fields are those that are the most advanced, as those will be the most attractive to the weevils that have overwintered in the ditch banks and leaf cover. Isolated fields that are the only winter canola fields in the area are also more prone to higher populations.
Populations are spotty, with not every field reaching threshold levels, but it is critical that scouting take place this week in fields in the more southern counties, to determine the level of CSPW activity. Thankfully, the daytime temps will be cooler for the next few days, so it will slow their activity and give some time to scout before the crop blows past the critical 10 -20% bloom stage to reduce risk of egg laying in the young pods that are forming on the plants.
Scouting is best done using sweep nets, assessing the fields every 3 or 4 days from bud stage until the end of flowering. Using a sweep net, take 10 sweeps (1 sweep = 180° arc) in at least 4 locations within the field and determine the average number of adults per 10 sweeps. Avoid sweeping at field edges and conduct sweeps on warm days between 11:00am and 5:00pm. Adults are much less active in temperatures below 15C so make sure to scout during the warmest hours of the day and check the forecast so fields are checked again on days that are at or above 15C. Windy days also keep adults off the plants, so scout during calmer hours to get a good sense of what populations are like.
The threshold for chemical control is 25 to 40 weevils per 10 sweeps during early flowering stages (10 to 20%). If thresholds are reached, an insecticide application is recommended. Products registered for cabbage seedpod weevil on canola are here on the Crop Protection Hub Keep in mind, bees are already active this spring so time sprays for very late in the evening or early in the morning when bees are less likely to be foraging in the crop. Contact local beekeepers at least 24 hours in advance so they can move their hives prior to spraying.
More information on cabbage seedpod weevil can be found on Crop IPM- Cabbage Seedpod Weevil and in a recent FCN article that Meghan Moran posted in September: https://fieldcropnews.com/2025/09/cabbage-seedpod-weevil-on-winter-canola/