Grape Root Borer Grape root borer is potentially the most destructive insect attacking grapes in Kentucky. Larvae of this insect tunnel into the larger roots and crown of vines below the soil surface. Borer damage results in reduced vine growth, smaller leaves, reduced berry size, and fewer bunches of grapes. Because damage is restricted to below ground, problems often go unnoticed until vine decline is observed. Damage caused by larval feeding can range from just a few feeding sites to complete root system destruction.
Adults are brown moths with thin yellow bands on the abdomen and resemble some paper wasps.
The front wings are brown while hindwings are clear. Male moths fly about in a manner similar to wasps. Larvae are cylindrical, cream-colored, with three pairs of true legs near the head and five pairs of fleshy abdominal prolegs each bearing two bands of tiny hooks. Adults emerge from the soil in mid summer. Eggs are laid on the soil surface, grape leaves, and weeds with eight days of adult emergence.