Gypsy Moth Defoliation on the Increase

Gypsy moth defoliation in Virginia this year has been estimated at over 112, ooo acres, an increase of 46% from last year. The most heavily impacted area was the GW National Forest in Augusta County extending into southern Rockingham County, which, combined, saw almost 43,000 acres of heavy defoliation. Another heavily impacted area for the third year in a row was northwestern Giles County, where more than 15,000 acres of forest was defoliated, most of that being in the Jefferson National Forest.

Gypsy moths were introduced into the United States via Massachusetts in 1869 and have been slowly spreading southward ever since. The first defoliation in northern Virginia was recorded in 1984 and the moths continue to spread slowly southwestward.

Dry spring weather predominated during 2005-2007, helping populations of gypsy moth to build up. This May, however, it was cool and wet at the right time, which can foster the development of a fungus disease affecting the moth population.

“In some areas, caterpillar mortality from disease appears to be quite high,” say VDOF Forest Health Specialist Dr. Chris Asaro . “The caterpillars die only when they are nearly full grown and most of the defoliation is done, so the disease doesn’t have much of an effect for this year. On the other hand, dead caterpillars mean fewer adult moths will be around this summer to lay eggs. So, next year’s defoliation could be considerably lower.”

Egg mass surveys will be completed in late summer and fall and will give a better idea of what can be expected next year.

For more information visit one or more of these sites:

VDOF Forest Health Site

VDACS

Virginia Tech Gypsy Moth Site

Appalachian Fire Learning Network

Scientists and managers from state agencies, the US Forest Service, and The Nature Conservancy (TNC) met July 8th -10th at Douthat State Park for the third workshop of the Appalachian Fire Learning Network (FLN). Hosted by the Alleghany Highlands FLN project, the workshop focused on collaborative efforts to restore forest communities dependent upon fire. Representatives attended from the three other demonstration projects in the network: Cumberland River, KY; Shawnee Forest, OH; and Southern Blue Ridge, NC. Each project reported on their planning efforts and accomplishments.

A highlight of the workshop was of course the field trip. We visited recent prescribed burns conducted by two Alleghany Highlands FLN partners, the Forest Service and TNC. Together both partners burned over 4,000 acres last year to restore pine and pine-oak woodlands. We also visited a globally rare “pine barrens” variant of the pine-oak/heath woodland communtity on Warm Springs Mountain. The challenges of restoring this fire-dependent community (likely a stand replacement regime) were a topic for much discussion.

Collaborators in the Alleghany Highlands project include TNC, USFS, Virginia Department of Forestry, Virgina Department of Game and Inland Fisheries, Virginia Department of Conservation and Recreation, and Shenandoah National Park.

More information on the Appalachian Fire Learning Network can be found at
http://tncfire.org/training_usfln_appsfln.htm.

Emerald Ash Borer Infestations Found in Fairfax County, Virginia

On July 7, 2008, an infestation of the emerald ash borer was discovered in dying ash trees by Andrew Brown, VDOF forester for Halifax County, while visiting family in a residential development in Herndon, Va., near the Dulles Access Road. Two days later, another infestation was discovered on the other side of Fairfax County in Springfield, just west of I-95. Both infestations appear to have begun some years ago, indicating that the wood boring insects, which have a one-year life cycle, have likely spread to many other areas. Eradication measures for this insect pest will, therefore, be very difficult to implement.

Officials from the Fairfax County Forest Pest Program, Virginia Department of Agriculture and Consumer Services (VDACS), Virginia Dept. of Forestry, and many others, are actively searching for more evidence of infestation in Fairfax and adjacent counties. VDACS will likely soon issue a quarantine that prevents all ash material from leaving Fairfax County. Additional counties will likely be quarantined as well if and when the borer is discovered there.

The emerald ash borer is a highly destructive invasive species that has already killed millions of ash trees in Michigan and Ohio and may, ultimately, cost billions of dollars in tree removal and replacement costs. Since its discovery in 2002 in the Detroit area, it has spread to seven additional states (Ohio, Illinois, Indiana, Pennsylvania, Maryland, West Virginia and Virginia). It is also found in Ontario, Canada.

While it spreads at the rate of about two miles per year on its own, this wood-infesting beetle can be moved great distances by human transport of infested wood products, particularly firewood. Firewood for sale in Virginia is brought in from many different states, and many out-of-state travelers bring firewood with them to go camping throughout Virginia’s state and federal lands. Most new infestations have been located either near campgrounds or adjacent to major interstate corridors.

All species of ash trees of all ages, sizes and relative health are vulnerable to the emerald ash borer. The insect is usually very difficult to detect because ash trees typically don’t show any obvious signs of infestation until one year or more after the insect has attacked the tree. By then, the insects will have moved on to attack other trees. Traps for monitoring the insect are available and have been widely distributed by VDACS. However, these traps are not attractive to the beetles from long distances and, therefore, aren’t highly effective for early detection and for precisely locating infested areas. Research for improving these monitoring tools is ongoing.

The only control measure available is to cut and chip infested trees. An effective systemic insecticide for individual tree protection has recently been approved and may be widely available within a year, but this will be very expensive and not practical for halting the progress of the insect. Over the long run, homeowners and municipalities should consider replacing ash trees with other species that are not susceptible to emerald ash borer. It is highly likely this pest will eventually become established across Virginia, although government officials, pest specialists and arborists will work together to limit and/or slow its eventual spread.

For more information on what you can do to abate the threat of exotic pests such as the Emerald Ash borer visit the Don't Move Firewood website