Archive:Poplar/Cottonwood Borer
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.
Contents |
Importance
Larvae attack the root collar and main roots of young trees in natural stands and plantings in the Southern United States. Structurally weakened trees may break over.
Look For:
• Stems broken at ground level.
• Light brown, fibrous frass in bark crevices near the base of the trees.
• Piles of light brown fibrous frass around the base of the tree.
• Roots with frass protruding from them.
• Legless, yellow-white larvae about 1½ inches long within the roots.
• Large, robust, longhorned beetles, 1 to 1¼ inches long, black with white cross-stripes.
Biology
Adults emerge in late spring and early summer and feed on the foliage and bark of young Populus shoots. Eggs are laid at or below ground level, and the larvae mine beneath the bark and into the heartwood and sapwood where they form extensive tunnels. Pupation occurs in the galleries. There is a 1 to 2 year life cycle.
Monitoring
Inspect young trees and nursery stock for adult beetles during the growing season. Inspect the root collar area for evidence of larval boring throughout the year. Consider treatment if 10 percent of the trees are injured.
Gallery
 Photo by Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org |  Photo by Mike Ostry, USDA Forest Service, Bugwood.org |
Control
• Remove unmerchantable and brood trees.
• Remove and destroy 3-year-old or older stool beds in nurseries.
• Apply an insecticide recommended to control adult beetles feeding on the foliage.
For Additional Information:
Solomon, J.D. 1979. Cottonwood borer (Plectrodera scalator) - a guide to its biology, damage, and control. Res. Pap. SO-157. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 10 p.
