20190410invasivepest_63906.jpg

Several times in the not-too-distant past, non-native insects have made their way into the Mountain State. Once here, they launched assaults on the state's forests.

Like an old Hollywood B-movie, The Invasion of the Foliage Snatchers has plenty of villains. Unlike a movie, it doesn't end well for the good guys. Every time a wave of invaders comes through, trees die by the thousands.

Berry Crutchfield, the West Virginia Department of Agriculture's plant and pest biologist, said invasive insects have wreaked havoc on the state's oak, hemlock and ash trees. Other invaders are out there, and Crutchfield hopes they never make it here.

"The two we're most concerned about are the Asian longhorned beetle and the spotted lanternfly," he said. "They have the potential to do a lot of damage."

Of the two, the Asian longhorned beetle constitutes the greater threat, because it has the potential to affect one of the state's most dominant tree families.

"It attacks completely healthy maple trees and kills them," Crutchfield said.

Like many invasive insects, the Asian longhorned beetle is not native to the United States. As its name suggests, it originated in Korea, Japan and Eastern China.

"It was first found in New York, in 1996," Crutchfield said. "Since then, it has been found in several other locations."

West Virginia has several species of native longhorned beetles, but they're no threat to the state's forests.

"The native species only attack trees that are dead, or are in the process of dying," Crutchfield explained. "The Asian longhorned beetle attacks live trees."

According to a fact sheet published by the U.S. Department of Agriculture, the beetle prefers red, silver and sugar maples, as well as boxelder and Norway maples. Maple trees are plentiful in West Virginia's hardwood forests, and Crutchfield said it could do considerable damage to them.

"We're very concerned about the Asian longhorned beetle," he added. "We don't want it to get into our forests. It would be catastrophic."

So far, it has been found in New York, New Jersey, Massachusetts, Ohio and Illinois. USDA officials try to keep it from spreading by cutting down infested trees and running them through whole-tree chipping machines.

"They've managed to keep this thing contained, so far, but we're always on the lookout for this insect," Crutchfield said. "We don't want it in our forest ecosystem."

West Virginia officials are also concerned about the spotted lanternfly, another species native to Eastern Asia.

"It was first found in Pennsylvania, in 2014," Crutchfield said. "It attacks tree of heaven, which is a pest tree in the forest, so, at first, we thought it would be great to have it. But it also causes damage to grapes and fruit trees, as well as oaks, walnuts and poplars. We don't want that thing to get into the state."

So far, spotted lanternflies have been found in New Jersey, Pennsylvania and Virginia. Crutchfield said Mountain State officials are "actively monitoring for it."

Crutchfield said the concern comes from the experience West Virginia has had with other invasive insects.

"Historically speaking, probably the most destructive invasive insect has been the gypsy moth, which came to the U.S. in the late 1800s in Massachusetts and got into the Eastern hardwood forests," he said. "It prefers oak trees and, for a while, it was doing extensive damage as it moved down through the Appalachians."

The main wave of the gypsy moth invasion has now worked its way across roughly two-thirds of West Virginia. Fortunately for the state's trees, spraying programs and a naturally occurring fungus have helped slow the advance.

"The fungus shows up during wet springs, and we've had a lot of wet springs in the last few years. The fungus has knocked the population way back," Crutchfield said. "We still have an active spraying program, and we're continuing to trap gypsy moths to monitor the species' advance. It's still out there and, potentially, it could come back strong at any time."

The damage wrought by gypsy moths was serious, but not total. Unfortunately for West Virginia's ash trees, that hasn't been the case since the emerald ash borer beetle made its way into the state.

"They were first found in Michigan, in 2002, and it had probably been there several years before anyone found it," Crutchfield said. "They couldn't quarantine it, so it started to spread. We started monitoring for it in 2005."

Officials didn't have to wait long.

"We first found it in 2007, in Fayette County," Crutchfield said. "During a 10-year period, from 2007 to 2017, we found it in every county in the state. It has either killed, or is presently killing, every ash tree in West Virginia. There aren't many left that haven't been infested."

The state's hemlock trees are faring considerably better, thanks to treatments to combat the hemlock woolly adelgid, a tiny aphid-like insect that kills hemlocks by sucking the juice from them.

"It was first found in the U.S. in Virginia, in 1951," Crutchfield said. "People suspect it was introduced in some nursery stock. It spread westward and eventually reached West Virginia. We're monitoring its progress within the state."

To minimize damage to areas considered critical for aesthetics or for environmental protection, Department of Agriculture workers treat hemlocks with chemicals that have proven effective at controlling the insect. In areas that haven't been treated, hemlock mortality in heavily infested areas has reached levels upward of 80 percent.

Crutchfield said the state's best defense against invasive insects is to have the public looking for them.

"We spend a lot of time in outreach, trying to get the word out," he said. "We talk to various adult groups throughout the course of a year, and we bring pictures of these insects. We're trying to get as many eyes out there looking for them as we can."

The agency has an email address, bugbusters@wvda.us, where people can send in photos of insects they suspect might be invasive.

"We ask people to send in a digital image and a location," Crutchfield said. "If it's a harmless lookalike, we can weed those out. If we think it's something we need to check out, we go check it out."

It's all in a day's work for those who hope to stop The Invasion of the Foliage Snatchers.

Tags