Invasive insects attacking trees
Add Fauquier to the list of Virginia counties where a destructive Asian beetle that could decimate ash trees has been found.
The Virginia Department of Agriculture and Consumer Services recently confirmed the discovery of the emerald ash borer in Fauquier and three other counties. The borer could wipe out ash trees across the United States, state officials say.
Fauquier is the third area county known to have the emerald ash borer infestation. The beetle was discovered in Stafford and Caroline counties in 2012.
In 2009, Fauquier was among numerous Virginia localities put under quarantine from transporting ash wood because the destructive beetle was found in neighboring localities.
Now it’s official that Fauquier is infested.
“It’s alarming. It’s definitely unsettling,” said Kyle Dingus, a Warrenton-based forester with the Virginia Department of Forestry.
“We’ve had this on the radar” since the metallic green beetle was discovered in Virginia in 2003, he said.
The emerald ash borer somehow made its way to the Detroit area in 2002. A year later, it was brought to Fairfax County on nursery stock and began attacking ash trees in that area.
Dingus said he’s seen damaged trees in the northern part of Fauquier, which is not far from the Front Royal, Skyline Drive area where some deforestation has already occurred.
“I’m kind of hoping for the best,” he said, noting that the department will continue to monitor the problem.
Thomas Snoddy, one of five foresters covering Fredericksburg and the counties of King George, Caroline, Stafford and Spotsylvania, isn’t surprised by the beetle’s spread.
“I think it’s a matter of when it comes, not if it comes,” he said of areas where the beetles haven’t been found yet.
Although the emerald ash borer has been in Stafford and Caroline for at least two years, Snoddy hasn’t seen much impact so far.
“I haven’t really had any calls from homeowners or landowners,” he said, noting that there isn’t a very big ash tree population in the Fredericksburg area.
He and other forestry experts say the beetles can cause a lot of damage before they’re discovered.
“I think we’re on the early end of the spectrum,” Snoddy said.
The beetles can spread easily because the larvae, which cause the damage, are hard to find.
The larvae burrow beneath the bark while feeding, disrupting the flow of water and nutrients and causing most of the trees to eventually die.
Infested trees that aren’t dead need to be removed and destroyed.
“Once you know there’s a problem, it’s usually too late,” said Chris Asaro, a forest health specialist with Virginia’s Department of Forestry.
“It’s a pretty grim situation,” Asaro said. “It’s just going to keep spreading until the whole state is infested.”
Virginia is one of 23 states under quarantine, prohibiting the interstate movement of ash logs, ash nursery stock and firewood.
The beetles have been found in 21 Virginia counties and seven cities, according to the state agriculture department.
“The presence of the emerald ash borer in Virginia threatens the loss of all ash trees in the Commonwealth,” Sandy Adams, VDACS’ Commissioner, said in a release.
Asaro said there is a way to save trees that haven’t been infested.
“Options for protecting individual ash trees from EAB are available,” he said in the VDACS release. “People with very large, valuable ash trees would be advised to contact a certified arborist who can treat these individual trees with an effective insecticide every two to three years.”
Scott Shenk: 540/374-5436
TINY WASPS DEFOLIATING OAK TREES
Virginia white oak trees are also under attack by an invasive species, though the threat doesn’t reach the level created by the emerald ash borer.
The Virginia Department of Forestry recently announced the discovery of the tiny gall wasps in six Virginia counties, including three in the area: Culpeper, Orange and Fauquier.
In a release, the department said calls have been coming in droves from homeowners concerned about defoliating oak trees.
The department has conducted air and ground inspections, which have shown the problem to be widespread, but mostly concentrated in Fauquier and Loudoun.
The gall wasp is a tiny insect that doesn’t sting and usually isn’t even noticed by people, according to the forestry department.
Infestations by this particular type of wasp—known as jumping oak galls and oak button galls—is uncommon, said Chris Asaro, a forest health specialist with the department.
But sometimes the galls can multiply and cause noticeable damage.
The galls form from eggs injected by adult wasps into the underside of the oak leaves.
Larvae develop in the galls, which are orange and the size of a sesame seed, Asaro said.
After the larvae emerge from the galls they leave behind a “‘pock-mark’ of dead cells at the point of attachment to the leaf,” he said. The “dead spots” can become so abundant that they kill the oak leaves.
The wasps have been pretty busy so far, with many trees losing between half and all of their foliage, Asaro said.
The good news is that healthy trees should be fine, although they might not look very healthy for a couple years.
The wasps, Asaro added, usually are gone within a year or two because predators eradicate them.
“While defoliation can be a significant stressor, a tree that is otherwise healthy will normally start to produce new leaves and survive, even when defoliation is near 100 percent,” Asaro said.
If the defoliation lasts more than two years, though, a tree could die, he said.
Northern Virginia Senior Area Forester Terry Lasher said people should wait to treat infested oak trees.
“Even if an oak tree looks bad for the rest of the year, it’s best to wait until the following spring to see if it leafs out normally,” he said in the department’s news release. “This usually indicates the tree is doing well,”
The problem doesn’t appear to be an issue in the immediate Fredericksburg area, said Karen Snape, one of five foresters covering the city and the counties of King George, Caroline, Stafford and Spotsylvania.
However, she said in an email that colleague Tom Snoddy has seen “some light, patchy damage to oak trees in Spotsylvania that he suspects may be the gall, but nothing like the outbreak described in the press release.
Snoddy said he has not received any calls from local landowners about problems with white oak trees.
Scott Shenk: 540/374-5436