Published on 04/14/97

Tiny Homesteaders Pitching Tents in Georgia Trees

Some tiny homesteaders are attracting attention these days as they pitch their silken tents in trees all over Georgia.

"What you're seeing are most likely eastern tent caterpillars," said Dan Horton, an entomologist with the University of Georgia Extension Service.

"They're present every year," he said. "But every 10 years or so, for some reason, we seem to have a great abundance of them."

Is this the year?

Horton doesn't think so, although callers to many county extension offices have reported some unusual numbers.

"From what I've seen around here," he said in his Athens, Ga., office, "we don't have that kind of exceptional population."

In places, though, their "tents" seem to be popping up everywhere.

"You'll find them in most of the wild cherry trees," Horton said. "They get into apple, peach and plum trees, too. And when populations are high, they'll feed on beech, birch, oak, willow, poplar and others."

The leaf-eating caterpillars don't seriously harm the trees, he said.

"For the most part, these are native insects attacking native trees," he said. "They've both been there a long time, and they don't seem any worse for the wear."

If they're infesting a specimen tree in your landscape, "they're easy to control with virtually any homeowner pesticide," he said.

"The problem is spraying the tree," Horton said. "If you have to spray over your head with a home sprayer, go well beyond the safety precautions on the label. Wear a hat, long sleeves and safety glasses at the least. You may want to wear gloves, too, and a dust mask (or make a mask with a handkerchief)."

The caterpillars are unlikely to harm a healthy tree. "The damage is usually only aesthetic," he said. "If the plant's health is already compromised, their feeding can further stress it."

Georgia has two groups of web-weaving forest caterpillars, he said: eastern tent caterpillars and fall webworms. Some differences between the two are obvious from a distance.

Fall webworms have two to four generations each year, depending on the climate and are active from early summer through fall. They spin their webs at the ends of tree branches, feeding in relative safety inside the leaves they enclose.

Eastern tent caterpillars are active only in spring, Horton said, They emerge at about the same time new leaves appear in cherry, apple and other host trees.

The caterpillars build their nests in the crotches of trees, he said. They don't feed inside the nests, but congregate there at night and in rainy weather. During the day, they may strip the leaves from branches within a yard or so of their nests.

"Wherever the larvae crawl, they leave a fine thread of silk behind," he said. "After a few days, you can easily see silken pathways from the webs to the first good feeding site."

When the caterpillars mature after four to six weeks, they scatter, spin cocoons and pupate. They emerge as reddish-brown moths, which deposit hundreds of eggs in masses that look "like large wads of dark brown bubble gum wrapped around small twigs," he said.

The little wads of eggs will stay through the summer, fall and winter. About nine months later, they'll hatch into tiny larvae that will pitch their tents in the trees again.

Dan Rahn is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.