Pollen beetle

The pollen beetle (lat. Brassicogethes aeneus) is a small coleopteran insect belonging to the Nitidulidae family. The adult beetle is characterized by its oval shape, measuring 2–2.5 mm in length, and a distinct metallic blue-green or bronze sheen. It is a major agricultural pest known for causing significant economic losses in various oilseed and horticultural crops across the globe.

The pest primarily targets crops from the Brassicaceae family. Winter oilseed rape is the most susceptible host, followed by cabbage. However, when preferred hosts are unavailable or during mass migration events, the beetle may also damage the flowers of sunflower, soybean, hemp, fodder beet, as well as melon and watermelon crops, causing localized but significant physiological stress to these plants.

The life cycle of the pollen beetle is strictly synchronized with the flowering phenology of its host plants. Adults overwinter in soil debris or forest litter, emerging in early spring when temperatures reach 10–12 °C. Females lay eggs inside unopened flower buds. The larvae feed on pollen and floral tissues for several weeks before returning to the soil to pupate. There is typically one generation per year.

The economic damage is primarily caused by the adults. They pierce through the walls of young buds to reach the pollen inside, leading to bud abortion, necrosis, and premature drop. This direct injury prevents the development of pods and seeds. While larvae also consume pollen, the initial destruction by adults during the bud stage is the critical factor that determines the overall reduction in crop yield.

Effective management requires a combination of monitoring and timely chemical intervention. Because the beetle is most harmful during the bud formation stage, preventive spraying is essential. Key strategies include:

• Implementation of crop rotation to reduce local populations.
• Monitoring using yellow water traps to track migration and population density.
• Application of insecticides only when economic thresholds are exceeded.
• Promoting rapid crop canopy development through balanced fertilization to minimize the vulnerability window.