It might sound like a B-grade horror movie, with a title like “Killer Baby Bug Eats Victims Alive.” But it’s a true tale, and it’s unfolding now in Northern Virginia.
The insect’s prey is not human, but ash trees. The “killer” is the emerald ash borer, which is smaller than a penny and, as its name indicates, is metallic green. This beetle has killed tens of millions of trees in the United States and Canada since its initial discovery in 2002.
Although there are almost 200 million ash trees in Virginia, other tree varieties comprise 99 percent of the annual harvest. Ash is a more expensive wood, though. A conservative estimate of the amount loggers paid to landowners for ash in 2006 was $1.26 million, as reported in the November 2006 Virginia Department of Forestry Forest Health Review.
Ash is a familiar tree in urban and residential areas. Joe Rossetti, the area forester for Rappahannock and Fauquier counties, says about seven out of 100 trees in Virginia are ash. Ash trees prefer moist soil, and make up 10 to 12 percent of the trees along waterways.
Only the leaves of the ash tree are in danger from the adult beetle. It is the larvae that wreak the damage by eating the inner bark of the ash tree as it grows to maturity. As a result, less water and nourishment can move through the tree.
In 2003, the Virginia Department of Agriculture and Consumer Services (VDACS) learned of a shipment of infested trees from Michigan to a Maryland nursery. Fairfax County Public Schools bought and planted 16 of these trees. The emerald ash borer arrived in Virginia.
County and state workers cut and burned all ash trees within a half mile of the infested trees, according to the 2005 Virginia Invasive Species Management Plan published by the Virginia Invasive Species Council.
Afterward, no emerald ash borers were found in Virginia for four years, says Debra Martin, a cooperative agricultural pest survey coordinator with VDACS. Then, in July 2008, the beetle was identified in Fairfax County.
The emerald ash borer has been seen twice this year — on June 24 in Frederick County near West Virginia and in Prince William County on July 7. Neither discovery surprised Martin, because of the proximity to Fairfax and West Virginia. Rossetti reports that the ash borer has also been found in three places in Fairfax County this year.
“It’s spread regardless of anything we’ve done to try to stop it,” says Rossetti. Every year, since the first discovery in Michigan, the beetle has been identified in a new area of the U.S. and Canada.
In addition to Michigan and Virginia, the emerald ash borer is embedded in Ohio, Indiana, Illinois, Maryland, Pennsylvania, West Virginia, Wisconsin, Missouri, Minnesota, New York, Kentucky and Iowa. There are also infestations in the Canadian provinces of Ontario and Quebec.
The extension of the infestations tends to follow interstate highways, says Rossetti. This observation supports the hypothesis that people are carrying the emerald ash borer with them as they travel. For example, the beetle was found in Missouri 200 miles away from the nearest infestation. Ash borers can only fly a half-mile distance from its place of birth, according to the Emerald Ash Borer Information Network (emeraldashborer.info). Federal investigators are exploring how the bug could travel so far and not be discovered in between the locations.
Quarantines provide a way to slow down the beetle’s expansion. Under quarantine, no unprocessed ash wood, leaves, or sticks can travel out of the area. VDACS establishes and enforces the restrictions.
Arlington, Fairfax, Fauquier, Loudoun and Prince William counties, and the cities of Alexandria, Fairfax, Falls Church, Manassas and Manassas Park have been under quarantine.
“It’s definitely increasing, and in large measures increasing through movement of firewood,” Martin says. No firewood of any species can cross the boundaries of the quarantine. Ash wood is difficult to identify after it has been cut up.
On July 7, Clarke and Frederick counties and the city of Winchester were added to the roster of Virginia localities in quarantine.
“Because there’s so much firewood movement in northern Virginia, the decision was made to include Clarke,” Martin says.
The Shenandoah National Park prohibits firewood from being brought into the park. Wood most be gathered or purchase inside the park.
The quarantine causes some difficulty in moving hardwood around.
“Virginia does not have as large an ash population as some states west of us,” says Martin. “There’s a much more dramatic impact.”
In addition to its other responsibilities, VDACS hangs purple boxes in ash trees. Far from ornamental in nature, these two-foot long plastic constructions are designed to trap emerald ash borers. The intent is not to decrease the ash borer population, but to monitor its expansion.
Without the traps, it is extremely difficult to track the progress of the beetle, reports the May 2009 Virginia Department of Forestry’s Forest Health Review. Otherwise, one cannot see the presence of the insect until it has done the damage and left.
The U.S. Department of Agriculture supplies the materials. VDACS hires nine wage employees to install, monitor, and remove the traps, says Martin.
A lure of Manuka and phoebe oil hangs in the center of the trap. This scent attracts the beetle, as well as does the color purple, according to a Maryland Department of Agriculture. The box is coated with a nontoxic sticky substance.
“It’s large. And it’s hanging in the canopy of a lot of ash trees,” says Martin. “If they’re flying around they’re likely to smack into it.” Currently there are 3,400 to 3,500 traps installed in Virginia ash trees.
They are part of the second national survey that VDACS has joined.
No emerald ash borer was found last year on any of almost 3,300 traps. “This year we have two spots and we still have a month and a half to go,” says Martin.
Traps are set between the end of April and the end of May and will come down beginning in late August. The adult beetles are expected to be flying during this period. All traps are checked at least once and the lure is refreshed. Of course, the traps are checked again when removed.
There are 90 traps in Rappahannock County, says Sue Garvin of Sperryville. She is an emerald ash borer survey trapper for VDACS. Garvin spent several weeks in May and June driving around to find advantageous spots to hang the traps. Her first choice is on Virginia Department of Transportation right-of-ways. At times, though, Garvin knocked on doors to ask landowners for their cooperation.
“By and large, Rappahannock homeowners were delightful and welcoming and willing to participate in the survey,” Garvin says.
Part of Garvin’s job is to educate the public. It was routine, she says, when installing the traps, for drivers in Rappahannock County to pull over with questions.
“We’ve been entertaining lots of calls since the traps started going up,” Martin says. VDACS will help with identifying bugs by looking at pictures on Internet or by sending a staff person to the suspected tree.
Eradication and quarantine are the large-scale options to protect ash trees. Insecticides can be injected, but this is not feasible to apply to a forest, Rossetti says.
“For valued individual trees, that’s the best method to protect the trees,” says Rossetti. Insecticide is viable for two years.
However, if a homeowner discovers the emerald ash borer, Rossetti holds little hope.
“Sounds a little morbid, but start planting more trees.” Rossetti says. By the time the beetle is discovered in the tree, it’s impeding the flow of the insecticide through the tree.
Martin is more optimistic. The potential success of insecticide depends on the level of headway made by the beetle.
“The healthier the tree, the better it will be able to move that insecticide throughout the tree,” says Rossetti.
“Ash is a native tree and we don’t want to lose anything of those,” Martin says.
Homeowners should call VDACS in Richmond (804-786-3515) or the local extension office (540-675-3619) if they discover the emerald ash borer.