The leaf-chomping gypsy moth, like the pesky mosquito, is something Maryland residents will have to learn to live with, a state Department of Agriculture official contends.

The state has sprayed insecticide in 15 counties in an effort to protect forest land from defoliation by the insect, said Robert Tichenor of the Agriculture Department's gypsy moth control division.

But despite efforts to control the gypsy moth, its elimination is not likely, he said.

"In terms of trying to eradicate it . . . I don't think that is either economically or biologically feasible or necessary," Tichenor said. "It is going to be something like mosquitoes," he said. "You live with them, you tolerate them to a certain point, but somewhere along the line you say 'No, this is too much.' "

Aerial photographs to be taken later this month and in July will help officials determine the number of acres damaged by the gypsy moth caterpillars, which defoliate deciduous and evergreen trees, Tichenor said.

The caterpillar stages are the only damaging forms of the moth, because the adult moths do not feed, said Ruth S. Salvaggio, gypsy moth program coordinator for Montgomery County. The caterpillars hatch in April and complete most of their feeding damage by the end of June.

In one sense, Maryland officials said, they are winning the battle against the voracious insect.

"We are keeping ahead of it in the sense that we are very successful in protecting those lands that we prioritize," Tichenor said. Areas having priority for the spraying include high-use recreational areas, land under some type of management control, and areas of high real estate value.

"We are protecting as much of that as possible," said Tichenor, but he noted that preventing the spread of the insect by anticipating where it will crop up is a more difficult task.

Last year, gypsy moth damage of varying degrees was found on 83,488 acres of Maryland's approximately 2.7 million acres of forest land, Tichenor said.

This year, Tichenor said, he would "take a chance and say I don't think it is going to be higher than last year, but I don't expect it to be appreciably lower."

Meanwhile, the leaf-eating insect has landed in the District and may soon become a serious problem for some upper Northwest neighborhoods unless preventive measures are taken, according to the University of the District of Columbia's extension service.

"It's really bad right now, and we are getting dozens of calls a day from people wondering what to do," said Allen Jones of the Cooperative Extension Service, a service of UDC that provides agricultural information to the public. "But it's nothing like what it's going to be in a couple of years."

In this area the hungry gypsy moth caterpillars, which are identified by their rows of blue and red dots, feed on oaks and other types of trees. They can kill softwood trees after one defoliation; two or more defoliations can lead to the death of hardwood trees.

Jones said that although the moths have been discovered in small quantities all over the District, they can be found in threatening numbers only in some upper Northwest neigborhoods. Some residents of the Chevy Chase area, where groomed yards are lined with large oak trees, said they first started noticing the moth's voracious leaf-eating caterpillar just a month ago, and many have begun taking steps to prevent the caterpillars from destroying their trees.

Officials recommend that trees be wrapped in burlap, a method that can trap larvae and caterpillars as they ascend or descend a tree.

Salvaggio said trapped caterpillars should be gathered and destroyed in the afternoon and that homeowners should wear gloves or use a tool when removing them from the trees. The caterpillars can be dropped in soapy water or sprayed with it.

The gypsy moths were brought to the United States in 1869 in Massachusetts and eventually spread north to Maine and south to Virginia. The caterpillar, which hatches after nine months, feeds on leaves, shade and fruit trees, and shrubs. It can eventually devour entire forests.