Emerald ash borer spreading further in national park

STAUNTON — The emerald ash borer has made its way into a neighboring county and it's only a matter of time before the insect reaches Augusta County, destroying ash trees with it.

Adult emerald ash borer beetles were caught in surveillance traps near Mathews Arm Campground, Gravel Springs Hut, Pinnacles Picnic Area, Big Meadows Picnic Area and the South River Picnic Area, according to the park service.

These new finds show a huge jump from last year's detections in the northernmost portion of the park in Warren and Page counties.

This year's find also adds three new Virginia counties including Rappahannock, Rockingham and Madison, the park service said.

According to Rolf Gubler, a park biologist, emerald ash borers could already be in portions of Augusta County. But it could take a few years for the insect to spread fully to the surrounding area.

The infestation is spreading and the insect isn't going away, he said, and the park service will be focusing its efforts to survey and trap further south.

"At this point the detection is up on the Blue Ridge and it's kind of in the northern, northeastern direction," he said. "We're definitely focused on central and southern districts with trapping ... to see if the emerald ash borer is moving down the ridge."

The emerald ash borer eggs are laid on the outside of the bark, where they burrow into the bark and in the outer sapwood, making them hard to find. They create galleries or tunnels in the outer sapwood and disrupt the flow of water and nutrients for the ash tree, thus killing the tree.

If the insect becomes well established in Shenandoah, it could lead to upwards of 95 percent ash mortality, the park service said.

According to the park service, ash trees represent five percent of the park's trees, which collectively, these ash-containing communities make up 65 percent of the Park's forest or 126,883 acres.

The insect was first discovered in 2012, in Warren County, 11 miles southeast from where the borer was found in 2013.

The park has been trapping since 2009, Gubler said, with the eminent threat of the species coming closer into the park. The park is mandated to take care of the exotic, invasive species, Gubler said.

In April 2013, park staff began conducting preventive borer pesticide treatments on ash groves in developed areas and select sensitive plant communities in the northern third of the park, park officials said.

The project goals are to reduce hazard ash tree formation in developed areas and to preserve a portion of the park’s ash trees until approved biological controls become available, park officials said.

The project is expected to continue and expand in the coming years. Park staff treated 1,030 ash trees this past spring.

The goal of the project is to reduce hazard ash tree formation and to preserve a portion of the park's ash trees, including select high-conservation areas, mainly in the northern third of the park, Gubler said.

Once a tree is infected, it can die within five years, the park service said.

The species was first found near Detroit in 2002. Gubler said it's believed to have come to this country on a shipping container.

The borer can only fly up to a mile in one year, so the movement of the species is aided by humans transporting ash wood or firewood, Gubler said. Currently, surveillance has been amped up at campgrounds and picnic areas where visitors could bring in illegal firewood.

The threat is similar to the hemlock woolly adelgid that created high levels of decline and mortality for hemlocks. Gubler said the same could happen to ash trees once the emerald ash borer population is more established.

Follow Laura Peters @peterslaura and @peterpants . You can reach her at lpeters@newsleader.com or 213-9125.