Though entomologists warned that we're not out of the woods yet, surveys released yesterday gave the first indication that Anne Arundel County may be on the right path toward controlling its gypsy moth population.
The annual count taken each fall to determine the number of egg masses per acre appear to indicate that gypsy moth populations are stabilizing in the areas sprayed last May.
"Judging from the data, I believe we made the biggest impact ever this year in Anne Arundel County, and you may see things leveling off from now on," said Sally Hughes, regional entomologist for the state Department of Agriculture.
Last fall the state found more than 22,000 acres infested with 1,000 or more gypsy moth egg masses, but this year only 11,082 acres exceeded 1,000 masses per acre, Hughes said.
A community with more than 1,000 masses per acre is considered seriously infested and is eligible for free pesticide spraying from the state in May.
A limited budget forced the state to cut almost half of the eligible areas from its free-spray program in 1990. This year, Hughes said, the state will be able to spray almost all the eligible communities.
The majority of heavily infested communities, Hughes said, are east of Ritchie Highway, mostly in the Pasadena area.
The entire area around Mountain Road that was bypassed last year, including Riverdale, Lake Shore, Forest Glen, Brookfield and North Shore, is "almost assured" of being included in the state's spray blocks this year, she said.
On the other hand, much of the Benfield Road corridor that was sprayed last year, including Round Bay, Severna Forest, Kensington, Linstead on the Severn, Olde Severna Park, West Severna Park, Evergreen Estates, Colchester on the Severn and Rivendale, will be bypassed by the state this year because egg mass levels have dropped into the 100s.
To be eligible for the county's discounted helicopter spray program, a community must have a count of 100 egg masses or more per acre with a 50 percent canopy of mostly hardwoods.
County entomologist Richard Olsen was pleased that the various state, county and private spray program are having an impact, but warned that even levels as low as 250 egg masses per acre can result in defoliation in a single spring.
"I wouldn't say it's time to rejoice," Olsen said. "There is a direct positive correlation between egg masses and population, but it also depends largely on conditions. It's less predictable than we would like it to be."
"This may give some communities a breather, but when you have 250 or more egg masses, it's still crisis management," Olsen said.
The damage done by gypsy moth caterpillars to county oaks and other hardwoods has grown alarmingly over the last two years. In 1988,the state reported that no acres lost more than 60 percent of their leaves to the caterpillars -- the definition of defoliation. But in 1989, about 3,600 acres were defoliated; this year, the number losing over 60 percent of their leaves rose to 7,447.