Bronze Poplar Borer (Agrilus liragus)

From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance- The larvae girdle stems by feeding under the bark. Stems that are weakened or dying from other causes are particularly susceptible.

Look For: Dead or dying trees. D-shaped holes on the surface of the bark of the branches and stems. Zig-zag galleries on the wood surface of the branches and stems. (You will need to remove some bark with a knife to see these.)

Bronze poplar borer injury Photo by Mike Ostry, USDA Forest Service

Biology- Females lay eggs in bark crevices throughout the summer. Emerging larvae tunnel into the cambium of the branches and stem. The life cycle extends over two winters

Monitoring-  Inspect medium-age trees for signs of injury. If 10 percent of the trees become infested, treat or harvest the stand.

Control:

• Maintain healthy trees, fertilize, and water if possible.
• Cut and destroy infested trees.
• Apply a pesticide recommended for wood-boring insects to the stems and branches in early summer to control adults.