Rape blossom beetle

The Brachypterus rotundicollis is a small beetle species belonging to the family Nitidulidae, within the order Coleoptera. While often overlooked due to its small size, this insect represents a significant challenge for growers of various cruciferous crops, as it specializes in feeding on the floral structures of these plants.

The primary host plants for this pest include oilseed rape (Brassica napus), mustard, and wild radish. The beetles typically appear during the late spring, coinciding with the bolting and flowering phases of these crops. Their feeding habits are centered around the pollen and delicate floral parts, which are essential for the plant's reproductive success.

The lifecycle of this pest is synchronized with the development of its host plants. Adults overwinter in protected areas, such as soil debris or sheltered field edges. As temperatures rise, they emerge and migrate to host plants to feed and mate. Eggs are deposited within the flower buds, and the developing larvae continue to feed on the reproductive tissues before descending to the soil for pupation.

Damage caused by Brachypterus rotundicollis is primarily economic. By destroying the anthers and pistils, the beetle causes bud drop and prevents pod formation. In severe infestations, the cumulative damage significantly reduces the potential seed yield. Furthermore, the feeding wounds may predispose the plants to secondary fungal infections.

Integrated Pest Management (IPM) is crucial for controlling this species. Cultural practices such as maintaining healthy crop rotation and removing cruciferous weeds are fundamental. When threshold levels of adult beetles are reached, targeted insecticide applications are used. It is vital to time these interventions carefully to protect non-target species, especially pollinators, which are essential for crop productivity.