Agriculture Reference
In-Depth Information
heavy infestations, however, the larvae remain in the trees feeding around
the clock. Pheromone traps for monitoring gypsy moth and mating disrup-
tion materials are available but should not be needed in most areas.
Tent Caterpillars
Western tent caterpillars and forest tent caterpillars can become problems
in orchards, and their combined ranges spread across the United States and
Canada. These pests form conspicuous, web-like nests in trees, and the lar-
vae can quickly defoliate an orchard tree. Remove and destroy the tents
whenever you find them. Programs to control other lepidopterous pests will
also control tentworms.
Apple and Thorn Skeletonizer
The small, reddish-brown apple and thorn skeletonizer moth has a wingspan
of less than
⁄
2
inch and is found from Virginia to California and north
1
into Canada. The adults overwinter in bark cracks and crevices of the trees,
emerging in spring and laying eggs on the undersides of leaves. Although its
preferred host is the apple tree, this pest also attacks hawthorn, pear, cherry,
and plum trees. The larvae are about
⁄
2
inch long, yellowish-green caterpil-
1
lars with black spots. They can often be found dangling from silken threads
from infested trees and blow readily from one tree to another. The larvae
feed on the leaf tissues between the veins, creating a skeletonized or lace-
like appearance. They roll the leaves and pupate within the shelter, emerging
as adults to start a new generation.
Severe infestations of apple and thorn skeletonizer can virtually defoliate
the trees, and infestations are most serious following mild winters. In most
fruit-growing regions, expect at least two generations per year. Spinosad and
Bacillus thuringiensis
products are effective against apple and thorn skelet-
onizer, and rotating between these two products will help reduce resistance
buildup. Neem products should provide partial control, and applications of
Surround may reduce feeding and egg-laying.
