Reducing Bee and Other Pollinator Poisonings

It’s time to be scouting winter canola and winter pea fields for insect pests, and also the presence of pollinators and other beneficial insects before making treatment decisions. If treatment or action thresholds of 20 Cabbage Seedpod weevils in 10 sweeps for winter canola or 1 Pea weevil in 25 sweeps for winter peas have been reached, then you may want to consider applying an insecticide to prevent possible future economic loss.

As a general rule, it is recommended not to spray insecticides just before or during bloom, but if it is necessary, try to spray later in the day towards the evening or at night when bees are less active, or during early morning hours before the bees start to actively forage. Pesticides that have had time to dry on the plant may be less toxic to foraging bees. Also, consider making a perimeter application rather than the entire field if the heaviest pest pressure is on field borders.

Honey bee and lady beetle on winter canola.
Figure 1. Honeybee and lady beetle foraging on winter canola. Photo by Karen Sowers.
For more information on this topic, check out WSU Extension Fact Sheet FS174E Pollination and Protecting Bees and Other Pollinators.

For questions or comments, contact Dale Whaley by email at or by phone at 509-745-8531.
Washington State University