Whitemarked Tussock Moth
From Bugwoodwiki
|
Contents |
Importance
This tussock moth defoliates a wide variety of trees, but the sycamore is among its preferred hosts. It occurs throughout the Eastern United States and Southern Canada. Heavy defoliation causes growth loss and dieback but rarely kills trees.
Identifying the Insect
The yellowish, hairy larva (30 mm long) has a coral-red head and thoracic shield with a black dorsal stripe. Four yellowish, brushlike hair tufts occur dorsally. A pair of black hair pencils arises anteriorly, and a single hair pencil arises posteriorly. Male moths are gray with dark wavy bands on the forewings. Females have no wings. Eggs are deposited in flattened clusters covered with whitish, frothy material.
Identifying the Injury
Young larvae skeletonize the undersides of leaves. Older larvae disperse and consume leaf patches, eventually consuming all but the leaf’s midrib and main veins. Late-summer defoliation by large populations may cause a skeletonlike appearance to entire trees as well as entire stands.
Biology
Overwintering eggs hatch from April to June. Newly hatched larvae feed close together but often are dispersed on silken threads by wind. Larvae mature in 5 to 7 weeks and spin grayish, hairy cocoons on the underside of branches and in bark crevices. The pupal stage lasts 2 weeks. Females deposit 50 to 300 eggs in masses usually on or near the old cocoons. There are one to three generations per year. Egg masses overwinter on host plants.
Gallery
 Photo by James Solomon, USDA Forest Service, Bugwood.org |
|
| Figure 1c. - Young trees defoliated |
Control
Populations on small trees can be controlled by destroying the conspicuous, whitish egg masses. Insecticides may be needed.
References
Leininger, T.D; Solomon, J.D.; Wilson, A. Dan; Schiff, N.M. 1999. A Guide to Major Insects, Diseases, Air Pollution Injury, and Chemical Injury of Sycamore. Gen. Tech. Rep. SRS-28. Asheville, NC: USDA Forest Service, Southern Research Station. 44 p.
