Validation of lygus and other insect pest thresholds in commercial farms throughout Alberta

The Challenge

Insecticide spraying during late flower or early pod is becoming a common practice for lygus control on canola. Currently, there is no agreement on economic thresholds and limited data for the benefit of spraying at the mid pod stage.

The Project

Validate lygus bug economic thresholds in commercial canola fields while documenting landscape features that can influence risk of lygus damage.

The Results

The economic threshold of lygus bug is 2-3 lygus per sweep at early pod stage, as current canola cultivars appear to tolerate lygus damage better than previous varieties. As a result, lygus bugs are less likely to reach pest status in prairie regions. Spraying for lygus bugs at the traditional threshold of 1-2 lygus per sweep at late flower/early pod stage was found to potentially reduce yield, compared those left unsprayed.

Higher number of canola acres can mitigate risk of lygus bug damage, as lygus populations are likely to be diluted.

Grower Benefits

The economic threshold was found to be higher than previously determined, saving growers on insecticide costs while preserving beneficial insects.