Hungry gypsy moths that stripped thousands of acres of Maryland foliage this spring have left behind millions of eggs to hatch and fly next spring, state agricultural officials say.
The voracious insects this year ravaged twice the territory they did last year: 83,000 acres statewide this spring, compared with 42,000 last season and only three acres in 1980. They are expected to attack with even greater force in the future, agricultural officials said.
Egg masses can now be seen, as can oak trees left bare after their leaves were devoured by gypsy moth caterpillars. By eating the life-sustaining leaves, the moths can destroy the sturdiest of trees after an infestation cycle of two to four years. Forced to resprout leaves, the trees are drained of energy; many eventually succumb.
Leaves were stripped on 8,198 acres of rural Frederick County this spring. In Montgomery County, which had defoliation for the first time, trees on 181 acres were stripped in Bethesda and Chevy Chase, state agricultural officials said.
The surrounding counties of Howard, Anne Arundel, Prince George's, Calvert and Charles reported larger gypsy moth infestations, but said they had had no defoliation damage thus far, officials said.
The hardest-hit area in the state was Allegany County in the northwest, officials said.
As the insects continued their migration to the south, Virginia's foliage loss jumped from 375 acres in 1984 to 5,200 acres during the spring feeding season, with Loudoun, Fauquier and Arlington counties bearing the brunt of the damage, officials said
The District of Columbia, which has an increasing number of moths but has reported no destruction, is not immune to such damage, a Maryland agricultural official warned.
"The gypsy moth is moving in," said Nathan Erwin of the Maryland Department of Agriculture's special insect division. "We're at the front line of the southern gypsy moth infestation. It's something to be prepared for."
Erwin and other experts say that homeowners in wooded suburbs can join the war against moths by locating new egg masses so that they can be destroyed. The fuzzy beige masses can be found "almost anywhere outdoors," Erwin said, such as on the underside of tree limbs, on lawn furniture or in stacks of tires or tools.
Erwin advised homeowners to contact their local agricultural extension offices for information about destroying the eggs or having their property sprayed next spring.
The egg masses, which can hatch from 250 to 1,000 moths each, were laid in July and should hatch next April.
Beginning this month, experts will be locating and counting egg masses to plan for spraying and other efforts to combat the annual onslaught.
Maryland spent more than $1.5 million fighting the pest this year, including applying nontoxic pesticides, releasing gnat-sized wasps that destroy the moth's larvae but do not sting humans, and hanging lure tapes on trees. The tapes release an odor intended to confuse male moths and prevent them from finding females for mating.
When gypsy moth caterpillars emerge next spring, they can be identified by their rows of blue and red dots. The moths will emerge as adults in late June or early July and begin mating.