Scientists, Ash Borer Wage War In Trees

Some beetles must have survived, and some must have traveled farther than the half-mile estimate in 2003. By last year, the kill zone had grown to a 25-square-mile area. All told, more than 36,000 ash trees have been cut down and destroyed.

But the beetle has proved to be a tricky and resourceful insect. In recent weeks, the emerald ash borer was discovered for the first time in Charles County, in trees about two miles south of the newly enlarged kill zone.

"It tends to pop up any time we think we have it under control," said Carol Holko, chief of the state Agriculture Department's plant protection section.

The problem is that some beetles, particularly females, can fly farther than the half-mile scientists believe to be their limit. Others hitchhike on people or firewood that campers transport from campsite to campsite (an action now banned in Prince George's and Charles counties). And even though workers have pulled up and destroyed, by burning or chipping, all known infested trees, the beetles can survive in fallen branches or unseen roots.

Their knack for surviving and spreading has allowed them to disperse in recent years to Ohio, Indiana, Illinois, Pennsylvania, West Virginia, Wisconsin and Missouri. This year, the insects were rediscovered in Fairfax County after a five-year hiatus.

For Maryland, the discovery of the beetle along the northern tip of Charles has sparked some minor reevaluation. The infestation of about a dozen trees along Mattawoman Creek is believed to be related to the original outbreak in Clinton and Brandywine.

"There was some fear that the population had been there undetected for many, many years, which would have been really bad," said Dick Bean, field operations supervisor for the state's program that deals with the borer problem. "Now, we think they have been down here two or three years at the most. It hasn't had a chance to become widespread in Charles."

But after years of dealing with the persistent bug, state experts have grown cautious about saying or even thinking anything too optimistic.

Five years ago, when agriculture staff members started dealing with the beetle, they dubbed the program the Emerald Ash Borer Eradication Project.

Now, they mostly refer to it as "the program."

Holko, who is in charge of the project, said, "I'm not ready to say elimination is totally out of the question, but it is becoming increasingly less realistic."

There is also hope on the horizon, however, as knowledge about the insect grows, Holko said. Researchers in Michigan have begun experimenting with importing natural parasites from Asia that prey on the borer beetle. And they have developed sticky traps that emit an alluring smell to catch the beetle.

Some Maryland workers liken their efforts to those of a doctor fighting cancer. Their goal in part is to keep the cancer from spreading, to buy more time for a cure to be discovered.

"This is one tough and tricky insect," said Bean, who has been supervising field operations against the beetle since it emerged in Maryland. "You know, man can take a stance against Mother Nature, but I don't know that he can win. Mother Nature is pretty resilient."