Description of the Pest
Leadcable borer is a cylindrical black beetle, 0.25 to 0.35 inch long, that emerges from round holes in trunks or cordons of damaged vines and from dead wood during spring and early summer. The head of the leadcable borer is mostly concealed from above by a hoodlike pronotum. Larvae are 0.35 inch long and cream colored with a small, dark head. The larvae are C-shaped and may be found feeding in tunnels on the vine. This beetle is not a common pest of grape, but has been observed in San Joaquin County and North Coast vineyards. It has also been reported to infest oak wine barrels and corks.
Damage
Adults bore into wood to prepare egg tunnels. Leadcable borer larvae feed in trunk or cordon wood for up to 9 months during development, creating frass-filled tunnels that can weaken vine structure. They can reinfest the wood from which they emerge. Distribution of infested vines is typically localized within vineyards.
Management
The best method of control is good sanitation. Remove prunings and dead wood from the vineyard and destroy by burning or by thoroughly discing or flailing before adults emerge in spring. Remove dead or damaged wood from vines. Leadcable borer can become a chronic problem in infested vineyards and may take several years to control by cultural means. Leadcable borer adults may be controlled by insecticides applied for worms and other species when adult beetles are present. Chemical control is not effective against larvae inside the wood.