Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, May 29, 1990 TAG: 9005290330
SECTION: NATIONAL/INTERNATIONAL PAGE: A3 EDITION: EVENING
SOURCE: Associated Press
DATELINE: BOSTON LENGTH: Medium
"You can almost take that to the bank," said Charles P. Schwalbe, a U.S. Department of Agriculture expert.
In 1981, the last time the gypsy moth population exploded, the pest stripped the leaves from 12 million acres of trees and other plants in the Northeast.
Gypsy moth populations rise and fall in cycles averaging about seven years. Now, scientists say, the region is due for another boom - and a huge one.
Since 1981, the moth has been expanding its range about 10 miles a year from New England, stripping foliage as far south as Virginia and Maryland and as far west as Ohio.
Infestations also have been found in California, Oregon, Washington and Colorado, where the larvae apparently were unwittingly transported by humans, said Schwalbe, director of USDA's Animal and Plant Health Inspection Service.
The gypsy moth actually is a danger in its caterpillar stage, eating more than a square yard of foliage by the time it matures.
The attack against the pest has primarily involved spraying of Baccillus thurigiensis, a bacterium known as Bt that attacks the moth's digestive tract, and use of diflubenzuron, a chemical. But they haven't stopped the pest.
Scientists are looking to other methods, including release of sterilized males to interrupt the moth's breeding cycle and use of the pest's natural enemies, including the white-footed mouse and nine kinds of parasitic insects.
A Japanese fungus is credited with protecting large sections of western Massachusetts last year.
The most promising development, some say, are viruses such as gypchek, which attacks the gypsy moth from the inside.
Martin Shapiro, a scientist at USDA's Insect Pathology Laboratory in Beltsville, Md., developed and is testing a virus he nicknamed Abby - for the town of Abington where it was isolated - that apparently kills more moths faster. But it works best in a large moth population and loses effectiveness in sunlight.
Coming soon, Shapiro said, is the potion that will make Abby the gypsy moth's nightmare. He said laboratory policy bars him from disclosing details.
Even with all guns blazing against the gypsy moth, however, humans can hope only for a stalemate, scientists say.
"You can control it, but when you're talking about eradicating the gypsy moth, there ain't no such animal," Shapiro said. "We do a good job with dodo birds and passenger pigeons, but there's virtually no insect that's been eradicated."
A French political exile, Etienne Leopold Trouvelot, imported the pest from France to produce a disease-resistant strain of silkworm. In 1868 or 1869, the moth escaped into Trouvelot's back yard in Medford. By 1923, the moth had spread throughout New England.
by CNB