Bug Off!

Notice a flash of purple in your peripheral vision as you’re driving north on the Route 611 Bypass lately?

Look more closely and you might see what look like bright paper lanterns hanging from trees about a mile apart from each other.

They’re not cast-asides from some late-night party. They’re actually insect traps designed to monitor the impending infestation of emerald ash borers, the non-native, wood-boring beetle that’s responsible for much of the destruction of ash trees in North America.

The survey is being conducted in a cooperative effort between the U.S. Department of Agriculture and state agencies.

“We have not detected emerald ash borers in Bucks County or in surrounding counties at this time,” according to Sven-Erik Spichiger, an entomologist with the Pennsylvania Department of Agriculture who’s working with the monitoring program.

But bug experts agree, it’s only a matter of time.

“It’s been a hot topic for awhile, but Bucks County and eastern Pennsylvania haven’t been hammered by them yet,” said Scott Guiser, Service educator.

The Emerald Ash Borer is native to Asia and was first detected in Michigan and neighboring Windsor, Ontario, in 2002. Bug-watchers figure the pest likely arrived via wooden shipping crates.

The insect, which damages both foliage and the tree itself during its life cycle, is moving eastward, and several states now count them as part of their current insect population.

Western Pennsylvania saw its first one in 2007.

Since then, the pesky beetle has moved through two-thirds of the state. Cumberland County – just west of Harrisburg – is the closest county to Bucks that has detected emerald ash borers.

The traps were hung in May and will remain up and monitored until about the end of August, according to Spichiger. About 61,500 traps were scheduled to be positioned in 48 states, excluding Hawaii and Ohio.

The Doylestown area is participating in a grid-based survey. Traps are placed within each cell of a 2 x 2 mile grid where ash trees are found.

The traps are spaced as uniformly as possible within the grid, taking into consideration accessibility and the presence and condition of the ash trees, said Spichiger.

The three-sided, two-foot-high prism traps made out of corrugated plastic are covered in a sticky glue designed to hold the targeted insects.

They’re purple for a reason, Spichiger said. Ash tree leaves emit a light wavelength that is purple in color and attracts the insects, he said.

The traps also contain two lures: oils from the manuka tree and a chemical called Z-3 Hexanol, which are compounds found in ash bark.

The traps are hung in or near ash trees in high-traffick areas, such as the Route 611 Bypass.

That's because many of the borers hitch a ride in hardwood firewood, and trucks delivering their firewood loads may make rest stops for gas or food near those sites – possibly unleashing some unwanted buggy freeloaders to the area as well.

The destruction caused by the bug poses a threat to the state’s $25 billion hardwoods industry.

In April, a statewide ban restricting the in-state movement of ash materials and all hardwood firewood was lifted, but a federal quarantine remains in effect. Since the beetle has moved rapidly across the state, the thought was that the in-state ban was no longer productive.

The peak period for adult infestation is about the third week in June, said Spichiger.

Adult Emerald Ash Borers are dark green, one-half inch in length and one-eighth inch wide, and fly only from early May until September. Larvae spend the rest of the year beneath the bark of ash trees. When they emerge as adults, they leave D- shaped holes in the bark about one-eighth inch wide.

Lots of developers use ash trees in their landscaping plans, said Guiser, because they grow fast, they’re hardy and not many pests affect them.

Once emerald ash borers make their presence known, “you can protect them with insecticides, but that can get expensive.”

There’ll be expenses, too, associated with trees that die because of the borers, since they’ll have to be removed and disposed of without causing the bugs to relocate to a new home as well.

Typically, the emerald ash borer beetles will kill an ash tree within three years of the initial infestation.

Unlike the gypsy moth crisis that hit the area about 30 years ago, these bugs are more than just “nuisance pests,” according to Spichiger.

“We’re talking total destruction,” he said. Gypsy moths can cause trees to die, but the emerald ash borers can cause enough devastation to “wipe out whole genuses of trees.”

“In some areas of Bucks County, ash can be as high as 20 percent in some of forested stands,” said Spichiger.

Spichiger said the findings will be reported at the national level and evaluations will be made for future management options, he said.

One of the alternatives may be utilizing parasitic wasps, which have been shown to keep them “mildly in check,” he said.

For those wanting more information or to report seeing an emerald ash borer, call the hotline at 1-866-253-7189 or e-mail badbug@state.pa.us.