Beetles could spell disaster for ash trees

By Katie Demeria

Sixty-five emerald ash borer beetles were recently discovered in the northern end of Shenandoah National Park, near Front Royal. The park’s ash trees are in trouble.

The beetles were originally accidentally introduced to the United States from Asia and were first discovered in southeast Michigan in 2002, according to a park news release. They have been moving steadily southeast ever since.

According to Shenandoah National Park biologist Rolf Gubler, a single beetle was found near Front Royal in a trap in August of 2013. The 65 found recently near Front Royal were all adults.

“To find that many beetles in a trap suggests that they’ve probably been there for two or three years at least, for them to reproduce and produce that many adults and go through that many generations,” Gubler said.

The beetles are a half inch long and metallic green. They lay eggs in the ash tree bark, then the larvae “burrow under the bark and create feeding tunnels that cut off nutrient and water flow to the tree,” the release stated.

The tree dies within three to five years, it added.

As of now, it is unclear how vast the infestation will be.

While ashes make up over 5 percent of the trees in the forest, they are represented in 65 percent of the forest community. The trees are dispersed throughout the park, which may limit the infestation.

Botanist Wendy Cass pointed out that hemlock trees only made up half of 1 percent of the tree population. The impacts of the hemlock woolly adelgid infestation several years ago, though, are still evident in the park.

“And what makes this particularly damaging, this emerald ash borer — it is fatal to the trees. Fatal. End of story,” Cass said.

The park has been monitoring emerald ash borer beetles since 2009. Cass and Gubler said park officials have been taking steps to suppress the outbreak since the spring of 2013.

“We started a proactive EAB suppression program and used different types of pesticides,” Gulber said. “We’ve been treating 1,200 to 1,500 trees per year in the northern third of the park, particularly trees that are in sensitive forest communities.”

Gulber said the park has also been treating trees that are along Skyline Drive or in developed areas like campgrounds.

That type of treatment, Cass said, can only go so far, though. Not only does the pesticide have to be reapplied, but it also kills other types of insects that feed off the tree, so it must be used sparingly.

“All of that hopefully will buy us some time to come up with better treatment options,” Gubler said.

Visitors will likely not notice the infestation for several years, he said. The insects fly slowly, at less than one mile per year.

“It’s going to be interesting to see what happens,” Gubler said. “There’s been some research to suggest, in the aftermath of an infestation, woodpeckers come in and are a pretty decent population limiter, attacking the larvae in those infested trees.”

“It remains to be seen how effective they will be, or how effective our disbursed ash population will be,” he continued.

Contact staff writer Katie Demeria at 540-465-5137 ext. 155, or kdemeria@nvdaily.com