Recently we have had a number of phone calls about worms on cedar trees. This is actually the juniper budworm. The Texas A&M Forest Service has a great publication about the juniper budworm and its control. The following is an excerpt from their publication.
“The small green larvae attack the tips of Ashe juniper (aka “cedar”) trees. As they feed, they web the foliage together and much of it will turn red or brown. The actual impact of this little caterpillar to the juniper trees is unknown.
It is a moth (Lepidoptera) in the family Tortricidae and has the Latin name Cudonigera houstonana (Grote). It is closely related and similar in appearance to the spruce budworm, a major defoliating insect pest of true firs in the eastern and western forests of the United States and Canada.
As the larvae feed in the juniper foliage, they construct silken tubes and pupation occurs in the shelter where the larvae fed. The adult moths are about 1/4-inch long and are similar to the color of dead Ashe juniper foliage. They have a mottled tan and brown color pattern on their wings. They are active mostly at night and are attracted to lights. They generally remain at rest on the host plant during the day and only fly when disturbed. Unless they fly, they are difficult to detect.
It is not known exactly what impact the juniper webworm will have on the Ashe juniper in Central Texas. It is not known if defoliation by this insect will cause juniper mortality. It is not known if feeding by a second generation of larvae will cause additional damage to trees that have already been impacted. So, that raises an important question. “What should landowners do about this pest?”
In rural, unpopulated areas, control for the juniper budworm is not recommended and probably not feasible. However, landowners might want to consider applying direct control when the pest occurs on high value landscape or yard trees. It should be remembered that natural controls in the form of parasites and predators currently are present. These include wasps, flies, spiders, birds and others. Removing infested branch tips by hand could be effective on individual trees. Some recommended insecticides for juniper budworm include Bacillus thuringiensis variety kurstaki, Mimic and Orthene.”
Please contact David Winkler at the Texas A&M AgriLife Extension Service for more information. 254-435-2331