They barged in without an invitation, clueless about hostess gifts and manners. They ate like they were starved. They even pitched a tent in the back yard.

        But there's something worse about Eastern tent caterpillars: They're planning to come back next year, hungrier, with more kids.

        Eastern Tent Caterpillars in trees are giving local agriculture and gardening experts fits because of the complaints they are getting asking: What should we do?

        “Right now,” said Joe Boggs, horticultural specialist for the Ohio State University Extension, Hamilton County/Southwest District, “there's not much people can do about it.”

        By the end of next week, most of the fuzzy little worms with the white stripes will be fluttering around as moths.

        While some homeowners say the caterpillar problem is the worst they can remember, Mr. Boggs says, from all indications, “It's a building year.

        “It's bad,” he said, “but not as bad as it could be. I suspect the populations next year could be even higher . . . They tend to have an 8- to 12-year cycle.”

        One or two colonies can completely defoliate a small tree, said Don Eberwine, horticulture program assistant, the Ohio State University Extension, Butler County.

        Trees can produce new leaves, so the attack is usually not fatal, he said.

        But for an already stressed tree, defoliation can be more serious, said Mr. Boggs, who cited a seasonal “moisture deficit” of 7 1/2 inches of rain.

        For trees with caterpillars, he said, people “should take particular care that they aren't drying out.”

        Eastern tent caterpillars are easily identified when they build their white silk nests in the crotches of small trees or where several limbs meet on larger trees. They have a solid white stripe down their backs.

        The caterpillars prefer the leaves of wild cherry, ornamental apple, cra bapple, plum, peach and cherry trees. Occasionally they will form nests in ash, birch, willow, maple, oak and poplar.

        “They really went after the crab apples this year,” Mr. Boggs said.

        When the caterpillars move from one food source to another, they can be seen — by the thousands — on streets and roads, driveways, sidewalks, patio furniture and houses.

        Soapy water works well in early stages of development, and Bt (bacterial spray Bacillus thuringiensis) helps control them in later stages.

        Gardeners are discouraged from burning nests or pruning them out of the trees.

        “It's frustrating because the trees look bad, but new leaves will come in,” said Cindy Graham, a spokeswoman for the Boone County Extension, where staffers have been getting “numerous calls. It's just one of those things.”

Caterpillar development

               There are four stages in the development of the eastern tent caterpillar: egg, larva, pupa and adult.

        The winter is spent as an egg on the host plant. The eggs hatch in early spring as the tree begins to bud. Little caterpillars spin threads as they migrate up and down branches. Tent building begins a couple of days after feeding.

        Larvae, which leave the tent to eat several times a day, become full grown about six weeks after hatching.

        That's the stage that gets attention. They are about 2 inches long, black, sparsely hairy, with some white and blue markings on their sides. There is a white stripe down the middle of the back. When mature, larvae migrate down tree trunks and form cocoons on bark, in grass and under nearly any object.

        After about three weeks in a cocoon, adult reddish-brown moths begin emerging.

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