BYGL Bug Bytes April 17, 2008 FOREST TENT CATERPILLAR EGG HATCH
| FOREST TENT CATERPILLAR EGG HATCH |
 |
 |
 |
 Participants in the Cincinnati BYGLive! at Spring Grove and Arboretum on Monday found newly hatched forest tent caterpillars (Malacosoma disstria) cavorting among flower parts on a white ash. With leaves not yet expanded, the flower parts were the only food available. The tiny caterpillars were at first difficult to find, but an empty overwintered egg mass covered in silk alerted the group that the game was afoot. Of course, this game of hide-and-seek will soon change. Heavy localized defoliation was experienced in southwest Ohio last year. The resulting large numbers of overwintered egg masses that are currently being found indicate the region may see significant numbers of caterpillars again this year. The caterpillars will feed on a wide variety of deciduous trees including ash, sweetgum, oak, birch, cherry, aspen, elm, basswood, and sugar maple. Baldcypress also serves as an occasional host. High populations can completely defoliate large trees. Fortunately, since the defoliation occurs very early in the spring, healthy trees are able re-foliate in time to produce sufficient carbohydrates to support spring growth next year. Despite its common name, forest tent caterpillars construct only rudimentary mat‑like silk nests on leaves or bark. The caterpillars are gregarious during early instar stages with colonies containing 100-300 individuals. They will remain in colonies during the day, and feed on leaves at night. When disturbed, or when the caterpillars run out of food, they may become a nuisance by spinning down from the trees on silk threads. As the caterpillars develop, they disperse from the colonies and become solitary feeders. However, last instars will often reconvene the mass meetings creating collections of dramatic writhing patches of hairy caterpillars on tree trunks and branches. Forest tent caterpillars have short grayish-white hairs, and distinct white markings running down their backs. These markings have been variously described as looking like "foot prints," or as being "keyhole‑shaped." The markings are flanked by cobalt blue lines running the length of the caterpillars' bodies. Trees should be closely monitored and early instars targeted for control if the population is high. Later instars are voracious feeders and produce rapid defoliation. Effective treatments include the naturally occurring bacterium, Bacillus thuringiensis (Bt), applied to early instar stages, as well as other insecticides labeled for general caterpillar control on the targeted plant host(s). For more information, see: 
|
|
| Last Updated ( Thursday, 17 April 2008 18:20 ) |
