How to Manage Pests

Pests in Gardens and Landscapes

Branch and twig borer—Melalgus confertus

The adult borer is a dark brown beetle, cylindrical in shape. The immature stage (grub) is white, fleshy, enlarged just below the tiny head, and appears legless. It is typically curled up in a C shape.

Life cycle

Damage

New shoots (8 - 10 inches long) wilt or break off during windy weather. Close inspection reveals a hole or gnawed area in the crotch formed by shoot and spur. Larvae burrow into wood at dead or dying parts of vines, plugging the tunnel behind them with sawdustlike frass and chewed wood.

Solutions

Prune out dying and dead parts of vine and remove or burn all prunings before March, as these are breeding sites for beetles. Keep area free of prunings and wood cut from fruit and nut trees and ornamentals. Pesticides should not be necessary.

Branch and twig borer adult
Branch and twig borer adult
Damage to cordon
Damage to cordon
Twisting of cane
Twisting of cane

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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