Columbia, SC - From the South Carolina Forestry Commission:
COLUMBIA, SC - Speak softly and carry a big stick. That advice is historically associated with Teddy Roosevelt, but forest health experts with the SC Forestry Commission also say it may be the perfect way for dealing with a certain pest now in season, the eastern tent caterpillar.
Each year South Carolinians notice tent-like structures forming in the branch crotches of their cherry, crab apple, and apple trees. While not destructive, they are unsightly to many of us and most homeowners would prefer not to have those silken, webby circus tents woven into their landscaping.
Laurie Reid, an insect and disease specialist with the Forestry Commission suggests merely swiping at the tent masses with a long pole or stick. "It sounds crude, but it is the safest way to deal with a pest that is merely offensive or annoying. Chemicals aren't necessary for this one," Reid said.
With the tents come the insect itself. The Eastern Ten Caterpillar has long brown hairs, a white stripe on the back which is bordered by yellow-brown and black lines, and blue and black spots on the sides.
It can also be found on ash, birch, blackgum, willow, witchhazel, maple, oaks, poplar, peach and plum trees, although your cherry trees are its preferred hosts.
The tent building is just one phase of this insect's year-long lifecycle. Each summer (usually in June or July), the adult female moth will lay 100-300 eggs in a dark brown varnish-like egg mass around a small twig. The caterpillars do not hatch from the eggs until the following spring, typically in March and April when the cherry buds are breaking.
After hatching, the caterpillars collectively make the tent and begin feeding on the newly emerging leaves. The caterpillars will also venture out from the protective nest to feed. After several weeks, the fully-grown caterpillars will leave the nest for a final time to find a protected place to make their cocoons (pupate).
Early this summer, the light brown adult moths will emerge from the cocoons. After mating occurs, the female will lay eggs and the cycle will begin again.
While a little nibbling occurs, these insects do not completely defoliate your trees. Eaten leaves will reappear quickly.
"It's unfortunate for them," Reid says, "but they are often mistaken for the fall webworm which we see in autumn."