Gypsy moths give appetites, forests a rest

October 04, 1991|By Mary Knudson

The gypsy moth took a breather this year from its relentless march through Central Maryland.

Statewide, the number of trees stripped of their leaves by this insect with a voracious appetite dropped 43 percent this year, state agricultural officials announced.

"There appears to be a virtual collapse of the gypsy moth in Howard, Frederick and Carroll counties," said Linda Scott, an entomologist with the Maryland Department of Agriculture.

Howard County, which last year saw 5,080 acres of trees defoliated, lost only 91 acres this year to the gypsy moth caterpillar, which gorges itself on leaves in late May and throughout June.

Frederick, which in some years has seen as many as 14,000 acres stripped, had 358 acres affected last year and only 48 spoiled acres this year. And Carroll dropped off the gypsy moth map altogether this year. The pest also was much kinder to Baltimore County trees this season, leaving only 190 acres of trees bereft of leaves.

Overall damage from the gypsy moth "was lower than anticipated," Ms. Scott said, with serious defoliation on 75,180 acres of trees this year, compared to 133,062 acres last year.

Just why that happened isn't clear.

Lack of funds caused the state and some counties to cut back on the amount of spraying done from late April to early June to prevent gypsy moth damage.

The spraying program has been working well, Ms. Scott said, but may be getting some help from Mother Nature."

Natural enemies -- some viruses, for example -- in the environment are destroying large numbers of gypsy moths and caterpillars, and likely will continue to do so for another couple of years, she said.

But Marylanders cannot grow complacent, the scientist warned.

The pests will be back if suppression measures don't continue.

The extent of gypsy moth infestation in a community is important because just two years of defoliation can kill a mighty oak tree, Ms. Scott said. The plant dies from the shock of losing leaves, its source of food and energy.

Eight Maryland counties experienced more defoliation this year than last, according to the Agriculture Department.

After years without defoliation, Charles County had 134 acres of bare trees this year courtesy of the gypsy moth, Ms. Scott said. Other Maryland counties whose problems with the gypsy moths exacerbated were Cecil, Dorchester, Somerset, Talbot, Washington, Wicomico and Worcester.

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