Brassica pollen beetle

Systematic position. The brassica pollen beetle (Brassicogethes viridescens) is a member of the order Coleoptera and the family Nitidulidae (sap beetles). While smaller and often less numerous than its relative Brassicogethes aeneus, it acts as a significant pest in agricultural fields, specifically targeting crops within the Brassicaceae family.

Host crops and damage. The pest infests oilseed rape (canola), mustard, cabbage, and various wild cruciferous plants. Adult beetles damage the plants by chewing holes into flower buds to reach the pollen inside. This feeding process causes buds to wither and drop, which leads to significant yield losses due to the failure of pod formation in the damaged parts of the flowering raceme.

Biology and lifecycle. Adults overwinter in leaf litter, soil crevices, or dense vegetation. They emerge in early spring when temperatures reach threshold levels of approximately 10-12°C. Once active, they migrate to host plants. Females lay eggs inside unopened flower buds. Upon hatching, the larvae feed on pollen and floral tissues within the bud before descending into the soil to pupate. The species completes one generation per year.

Economic impact. The critical period of damage occurs during the budding phase. If the crop growth is delayed due to cool weather, the beetles have an extended timeframe to feed on the flower buds. This prolonged exposure can result in stunted, flowerless stems, which severely reduces the number of pods harvested at the end of the season.

Management strategies. Effective control is based on an integrated approach:

• Crop rotation to reduce overwintering populations in the vicinity of new fields.
• Monitoring field edges with yellow traps to detect migration waves.
• Applying insecticides during the early budding stage if economic thresholds are exceeded.
• Promoting rapid plant growth through optimal fertilization to shorten the susceptible development phase.