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Tree quarantine aims to ward off destructive beetle
As bugs go, it's not that impressive, but it packs a big punch. The little, metallic green emerald ash borer fits nicely on a penny, but its effect on American forests since it showed up a decade ago from the Far East has been huge – the death of up to 25 million ash trees, the pre-emptive eradication of millions more.
Sometime in the last few years, it set up shop in Herndon, less than a mile from Loudoun County. And as of July 21, the Virginia Department of Agriculture and Consumer Services included Loudoun in a five-county quarantine to try to slow its spread.
Moving ash trees, seedlings or wood products out of the quarantine area can bring fines up to $1,000. Fines from the federal government can go much higher – up to $1 million.
The beetles are known to be in Fairfax and Arlington. Prince William, Fauquier and Loudoun are quarantined to identify and slow the spread.
The beetle itself, from egg to adult, is regulated under the quarantine and cannot be moved out of the area. Also under the quarantine, by the Agriculture Department directive, are all hardwood firewood, ash nursery stock, green (not kiln dried and certified) lumber, "and other living, dead, cut or fallen material of the genus Fraxinus, including logs, stumps, roots, branches and composted or uncomposted wood chips."
Homeowners are free to cut down trees and to use the wood or burn it. Lumber can be taken to a mill in the quarantine area. No ash tree or wood can leave the five-county quarantine area without a permit from the state. Firewood can be cut in Loudoun and delivered to a customer in Arlington, in the quarantine area. It cannot be taken to a Clarke County customer.
From May until August, adult beetles fly around looking for a mate – they live about 10 days in this stage of their lives, and can fly up to a mile a day. The females then lay eggs in the deep bark cavities of an ash tree. In 10 days, the eggs hatch and the larvae burrow through the bark to the living layer of tree tissue, where they carve out extensive tunnels.
The following spring, ready to metamorphose into adults, they bore back out through the bark, leaving their signature D-shaped exit holes, and fly off to start the cycle again.
Their tunnels cut off the flow of nutrients to the limbs and leaves above. It can take several years, but the tree dies. Loss of leaves on the upper canopy is frequently the first sign of an infestation, said Bryant Bays with the Virginia Department of Forestry.
Even if humans can be prevented from shipping firewood and lumber and giving the larvae a free ride to new territory, the further spread of the pest is pretty much a given, said Frank Fulgham, program manager in the state office of plant and pest services.
Michigan tried eradicating every ash tree within a given distance of an infestation, Fulgham said. That didn't work, and it won't be done here.
"Eradication is no longer feasible, " Fulgham said. "We are looking to identify how big the spread is, and keep the insects from moving further out by man-made means. There's not much we can do about natural spread."
Leesburg's urban forester, Jay Banks, is pretty sure at least some of the ash trees along East Market Street are infested. The trees are already stressed by drought, by living on dry, compacted soil along a major highway, and by breathing gasoline fumes. They could be having trouble fighting off native borers.
But more than a few are losing upper leaves, and a few have the suspicious D-shaped exit holes.
Pesticides have been successful on individual trees, but are too expensive for a wood lot, Bays said. Researchers are trying to find a natural enemy -- a predatory beetle that dines on emerald ash borer larvae, perhaps -- before the ash follows the American chestnut into near-extinction.
For more on the quarantine, call the Virginia Department of Agriculture and Consumer Sciences at 804-786-3515.
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