Ricky Kilpatrick, Pollet, Dale K., Coolman, Denise | 4/19/2005 10:29:08 PM
For instance, the worms are stripping cypress trees in Caddo Lake of their foliage, and the experts say that as long as conditions are favorable, they could hang around and cause more damage.
Dr. Dale Pollet, an LSU AgCenter entomologist, said bagworms generally are seen starting in early summer through the late fall. The pests mature in late August or early September and attach their bags to branches or other objects. When they mate, eggs are laid in the bags and remain there through the winter, since there is only one generation of bagworms per year.
"The worms tend to be a problem on trees that are isolated or in urban settings," Pollet said. "They can be controlled by spraying them with insecticides, like Spinosad (a growth regulator) Bacillus thurengensis (Bt) or Orthene 75S, after the eggs have hatched."
It is best to spray these larvae in the afternoon or on cloudy days, Pollet said.
"During the heat of the day the caterpillars are inside the silken sacs resting. They begin feeding as the temperatures go down in the late afternoon or about dusk," the LSU AgCenter entomologist explained. "Spraying during the day causes the material applied to be broken down by temperature and ultraviolet light – thus having no effect on the caterpillars."
Pollet also said it is best to use a "spreader sticker" with these products to make sure they stick to the plant material to get optimum management with a single spray.
Ricky Kilpatrick, an LSU AgCenter forestry agent, said he recently observed infestations of bagworms on baldcypress trees in Caddo Lake.
"The worms are real common on cedar trees and juniper trees," Kilpatrick said. "But after receiving some calls about trees in Caddo Lake losing their foliage, I checked and found bagworms on the cypress trees."
Bagworms are caterpillars that live inside spindle-shaped bags, which they build to protect themselves against birds and other enemies. The worms defoliate junipers and other trees and shrubs in July and August.
"The worms have eaten all of the needles on some of the trees and have made the trees look like they're dead," Kilpatrick said.
Kilpatrick said the bagworm population appears to be declining, and Pollet said the worms should be slowing down about this time.
"But as long as there is food and the weather is good, there will be a few," Pollet said.
For more information on controlling insect pests or a variety of other topics, call your parish LSU AgCenter office or go to www.lsuagcenter.com.
Ricky Kilpatrick at (318) 965-2326 or firstname.lastname@example.org
Dale Pollet at (225) 578-2370 or email@example.com
A. Denise Coolman at (318) 644-5865 or firstname.lastname@example.org