Red-necked cane borer

The red-necked cane borer (Agrilus ruficollis) is a wood-boring beetle belonging to the family Buprestidae. It is a significant pest of blackberry and raspberry plants, capable of causing severe economic losses in both commercial and home gardens. The adult beetle is easily identified by its distinctive metallic black body and a bright, copper-red colored pronotum, which gives the species its common name.

The life cycle of the borer generally spans one to two years. Adults emerge in late spring or early summer, feeding briefly on leaves before mating. Females then deposit eggs on the bark of young canes near leaf axils. Upon hatching, the larvae bore into the cane and begin feeding on the cambium layer. This internal feeding creates a winding, spiral pattern within the stem tissues.

The most visible sign of infestation is the formation of galls (swollen areas) on the canes, typically ranging from 1 to 3 inches in length. Inside these galls, the larvae feed extensively, girdling the stem and disrupting the flow of water and nutrients. Infested canes often become brittle, exhibit stunted growth, or die back entirely, particularly above the site of the gall.

Management of the red-necked cane borer relies heavily on cultural control practices. The most effective method is to prune and destroy infested canes during the winter or early spring before the adults emerge. It is essential to cut the stems several inches below the gall and remove the infested material from the field for burning or deep burial to eliminate the overwintering larvae.

Chemical control can be implemented as a supplement to pruning, primarily targeting the adult beetle before egg-laying begins. Recommended practices include:

• Monitor the plantation for signs of adult activity starting in late May or early June.
• Apply contact insecticides during the peak period of adult emergence.
• Ensure applications are made before the bloom period to protect essential pollinators.
• Remove any wild blackberry bushes nearby that may serve as alternate hosts for the pest.