A New Strategy for Managing Canola's Most Costly Pest
Two introduced species cause most damage: Phyllotreta cruciferae and Phyllotreta striolata 1 .
Most active in warm, dry conditions when canola seedlings grow most slowly 5 .
Traditional economic threshold for intervention is when 25% of leaf tissue is damaged and beetles are actively feeding 1 .
Field Trials
Ecoregions
Plant Densities
Management Strategies
Scientists conducted 16 field trials across four ecoregions: Manitoba, Saskatchewan, Alberta-Peace River, and Alberta-Lethbridge 3 8 .
Research tested combinations of plant densities (low: 3.5 kg/ha, optimum: 7 kg/ha, high: 14 kg/ha) and insecticide management strategies 3 .
Study design allowed researchers to understand how factors interact across diverse growing conditions on the Canadian prairies.
As plant density increased, flea beetles per plant decreased significantly 3 .
Seed treatments generally provided better protection than foliar sprays alone 3 .
| Management Strategy | Low Density Yield | Optimum Density Yield | High Density Yield |
|---|---|---|---|
| Control (No insecticide) | Lowest | Intermediate | Highest |
| Seed Treatment | Low | Intermediate | High |
| Foliar Spray | Low | Intermediate | High |
Increasing seeding rate decreased canola defoliation specifically in plots with insecticide-treated seeds 3 . Higher plant densities enhance the effectiveness of seed treatments.
Monitor flea beetle abundance and species composition
Quantify damage to cotyledons and leaves
Test plant population effects on pest damage
Identify predation on flea beetles
Developing models that incorporate weather data, landscape features, and historical pest pressure to forecast flea beetle risk 6 .
Modifying habitat to support populations of beneficial insects that naturally suppress flea beetle numbers 6 .
Developing canola varieties with enhanced tolerance to flea beetle feeding through advanced breeding techniques.
Integrating plant density adjustments with targeted insecticide use creates more resilient canola production systems that benefit both farmers and the environment.
The future of canola production depends on weaving together multiple threads—plant density, chemical protection, biological control, and cultural practices—into a strong fabric of integrated pest management.