BLACKSBURG, VA. -- A fungus that causes pine trees to kill themselves is continuing its rampage in Virginia, doubling its already high infection rate in some areas during the last month, a Virginia Tech specialist said last week.

Tech forest pathologist Sam Alexander said procerum root disease, which he started trying to warn people about two months ago, is prevalent enough in western Virginia now that perhaps 16 percent of marketable Christmas tree farm and nursery pines have been lost this year.

At the rate the disease is spreading, Virginia could see $5 million to $6 million in losses, Alexander said.

"I knew it was developing, but no one expected it would reach this proportion this quickly," Alexander said.

David Gardner, a Virginia Tech extension agent in Floyd County, said the disease, which is carried by weevils that feed on the roots of numerous types of pine trees, has the potential to wipe out nearly half of Floyd's agricultural economy because so many people rely on the pine-tree industry for their living.

The disease has been around since at least the mid-1970s, but picked up steam this year after a warm winter that allowed the weevils to start eating about two months early. Suddenly, the disease has moved even faster during the last month, particularly in the Appalachians.

"In plantations we've seen, it seems to have doubled," Alexander said.

Western sections of Maryland, West Virginia and North Carolina also have been hit particularly hard.

John Torbert, who has a 25-acre farm in Floyd County and is vice president of the Virginia Christmas Tree Growers' Association, has seen the spread first-hand. He lost about 50 trees to the disease five years ago, but this year has had to destroy 500 to 700 trees.

"The disease seems to grow exponentially," Torbert said.

The fungus carried by the weevils triggers trees to produce sap to fight the disease. Eventually, the sap builds up so much it chokes off water and food the tree needs to survive.

Early symptoms include late budding and a lack of growth. The tree later wilts and the needles turn yellowish green and then reddish brown. Alexander recommends growers burn the infected tree, and then either remove the stump or treat it with pesticide.

The only preventive is to treat trees with lindane, which kills weevils.

Alexander is the only university scientist in the country known to be studying the disease, but growers also are hoping to get state or federal money for further research.