How to Manage Pests

UC Pest Management Guidelines


Branch and Twig Borer

Scientific name: Melalgus (= Polycaon) confertus

(Reviewed 10/14, updated 10/14)

In this Guideline:


The branch and twig borer is a slender brown beetle about 0.5 to 0.66 inch long. The body is cylindrical and the head and prothorax are narrower than the body proper. The beetle lays its eggs in the dead wood of a number of native and cultivated trees and shrubs outside the orchard. The larvae bore into the heartwood of the host and feed within this area for a year or possibly longer. Pupation occurs within the wood and adults emerge in early summer. They often fly to orchards where they bore into small branches on the trees. There is one generation per year.

DAMAGE     View photos of borer damage

Adults bore into small twigs and branches, making round holes, commonly at the axil of a bud or fruit spur or at the fork of two branches. One of the branches frequently dies. Branch and twig borer seldom causes economic injury and is found only rarely in apricots.


These beetles do not prefer healthy, vigorous growing trees. Provide sunburn protection by pruning appropriately. A good irrigation and fertilization program will keep trees in good health. Promptly destroy brush piles, which harbor these pests. Remove badly diseased or borer-infested trees and branches from the orchard each winter and destroy them before spring. Spraying for this insect is not recommended.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Apricot
UC ANR Publication 3433

Insects and Mites

W. W. Coates, UC Cooperative Extension, San Benito County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
K. A. Kelley, UC Cooperative Extension, Stanislaus County
J. L. Caprile, UC Cooperative Extension, Contra Costa County

Acknowledgment for contributions to Insects and Mites:
L. C. Hendricks, UC Cooperative Extension, Merced County

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