Archive:Poplar/Willow Shoot Sawfly
From Bugwoodwiki
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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.
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Importance
Young whips and suckers are damaged by the female during oviposition. Later, the larvae kill the growing tip by their tunneling. Attacked leaders die and break off, causing bushy trees.
Look For:
• Wilted shoots.
• A ring of small punctures around the tender shoot where wilting occurs.
• Green or black leaves on injured tips.
• Dead or dying stunted stems with hollow pith.
• Pinkish, apparently legless larvae or transparent cocoons within the pith.
Biology
The female sawfly girdles the stem of newly developing shoots with a ring of punctures made by her ovipositor and then lays an egg below the girdled area. The larva bore into the pith and feeds down the shoot until ready to pupate. After pupating, the adult emerges through a hole in the bark.
Monitoring
Inspect young trees and nursery stock for wilted or dying shoots during the growing season. Treat if 20 percent or more of the main stems are attacked.
Control
• If practical, clip and destroy infested shoots.
• Cull infested nursery stock in summer or at harvest.
• Treat young stands and nurseries with an insecticide recommended for boring insects.
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| Larva of willow shoot sawfly. |
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| Wilted shoot caused by sawfly. |
For Additional Information:
Solomon, J.D.; Randall, W.K. 1978. Biology and damage of the willow shoot sawfly in willow and cottonwood. Annals of the Entomological Society of America. 71: 654-657.
