Research aims to stop spread of emerald ash borer

DELAWARE, OH — Scientists are researching natural predators and genetic engineering to control the emerald ash borer, according to a recent article from the Associated Press.

One possible solution involves three species of stingless Asian wasps that are in quarantine in government labs in Michigan and Massachusetts. The female uses an egg-laying appendage to pierce the bark of an ash tree, where she will find and paralyze an emerald ash borer larvae and glue her eggs to it. Her offspring will feed on the beetle larva when they hatch.

Worried that the bug cannot be stopped, researchers are also looking at insecticide use, crossbreeding and breeding a tree that makes its own insecticide.

“What we need to do is contain this for as long as we can, to give research a chance to catch up,” Vic Mastro, director of the U.S. Department of Agriculture lab that detects and finds ways to eliminate exotic pests, told the Associated Press. “Ultimately, it would be good to eliminate this pest, but we don’t have the tools to do this right now.”

The U.S. and Canadian governments are sticking with a strategy of cutting down trees to keep the beetle from spreading, though this may only slow the spread of EAB. Still, the other potential controls are years away.

Organic farmers often control pests with a bacterial toxin that can target a specific insect. Researchers identified at least two toxins specific to emerald ash borer, which cause internal ulcers or paralyze their chewing parts. The next step is getting the toxin-making gene into the tree, taking advantage of a natural bacteria that inserts genes in plant cells, then getting a few cells to grow into a tree.

Others are trying to cross breed the EAB-susceptible American ash trees with Asian ash trees, which co-exist naturally with the EAB. Even if the cross works, there’s no guarantee that the tree’s genes will allow it to resist the borer. If they do, it will take decades of more crossbreeding to get an essentially American tree with Asian resistance.

And scientists said it is impossible to predict how natural controls such as the wasps will work until they’re released in the environment.

In other EAB news:

• Officials from the Ohio Department of Agriculture recently found the emerald ash borer in western Lorain County, OH. The discovery was made while examining ash trees along the Ohio Turnpike. Lorain County is located just east of Cleveland, causing officials to worry that the destructive insect could infest the city, where ash trees are prevalent along streets.

• According to an article in the Sault Ste. Marie Evening News, in Michigan, all ash trees within a half-mile of Brimley State Park where the invasive beetle was discovered in summer were downed and later burned to keep it from gaining a foothold.

The emerald ash borer threatens more than 700 million ash trees throughout North America. Ash trees infested with EAB typically die within three to five years. The invasive pest is already responsible for the death of more than 16 million ash trees.

Adult emerald ash borers are dark metallic green in color, one-half inch in length and one-eighth in. wide and fly from early May until September. Larvae spend the rest of the year beneath the bark of ash trees, and when they emerge as adults, leave D-shaped exit holes in the bark about one-eighth inch wide.