- Associated Press - Sunday, September 20, 2015

LITTLE ROCK, Ark. (AP) - Arkansas foresters have unleashed a teeny-tiny attack team against the emerald ash borer.

The invasive borer, a beetle, is seen as a mortal threat to all five ash tree species in the state (and possibly to native fringe trees, too), and 25 counties are under quarantine against it. These beetles burrow around underneath bark, killing the trees they infest within five years, sometimes faster.

Last week, the state joined 21 other states in an experimental, biologic counterattack using parasitic wasps, the Arkansas Democrat-Gazette (http://bit.ly/1KSsDJz ) reported. Harmless to people, these wasps lay their eggs on the eggs of the emerald ash borer, and when the eggs hatch, wasp larvae eat the borer larvae.

A small crew from the Arkansas Forestry Commission, the State Plant Board and the Animal and Plant Health Inspection Service (APHIS) spent Tuesday releasing these parasitic wasps near Arkadelphia, McNeil and Bluff City. No, they didn’t open a little cage and shoo tiny black wasps into the air.

In video clips posted on the Forestry Commission’s and the state Agriculture Department’s Facebook pages, state survey coordinator Soo-Hoon “Sam” Kim of the Arkansas Plant Board can be seen attaching a bolt of wood to a borer-infested tree near Arkadelphia. Kim inserts a screw hook into the trunk and hangs the 31/2-inch-long bolt of ash off the hook with a zip tie.

Inside the bolt were an estimated 100 pupae of the wasp Tetrastichus planipennisi, one of three parasitic wasp species known to feast on the borer in its native environment in Asia.

The team placed 30 bolts on 30 strategically selected ash trees. By now, adult wasps have emerged from the bolts and set about their life’s work, which includes hunting for borers and drilling through tree bark to reach the targeted eggs. Successive wasp generations will spread around the area.

The bolts of green ash, each 1 to 3 inches in diameter and weighing 1 to 2 pounds, were infested with borers and then with wasps at a U.S. Department of Agriculture APHIS biocontrol site in Brighton, Mich., where they were wrapped in plastic and shipped to Arkansas.

“These larvae are not a silver bullet for stopping the emerald ash borer altogether,” Kim said in a news release. “This is a population control effort, which hopefully helps us to manage their spread. Unfortunately, we cannot yet eradicate this invasive beetle.”

Under a USDA protocol, more wasps will be released this fall and then another round will be released in the spring. Tetrastichus is being used this fall, but other species — Spathius agrili and Oobius agrili — will be released in the spring.

The State Plant Board and Forestry Commission will monitor the three sites. Because it’s an experiment, landowners cannot order their own wasps to release, but information about pesticide options is at emeraldashborer.info.

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Besides being nice to have around, ash trees are important to the economy. They make up about 3 percent of the state’s mercantile timber stock, according to figures provided by the Forestry Commission, and are used in guitars, cabinetry, flooring and other familiar goods.

The trees also are important for wildlife and for erosion control in river valleys.

In 2014, adult emerald ash borers showed up in sticky traps set in trees in Columbia, Nevada, Ouachita, Clark, Hot Spring and Dallas counties. In 2015, the borers also showed up in Bradley, Calhoun, Saline and Union counties.

The State Plant Board has quarantined wood in 25 counties: Ashley, Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas, Drew, Garland, Grant, Hempstead, Hot Spring, Howard, Jefferson, Lafayette, Lincoln, Little River, Miller, Montgomery, Nevada, Ouachita, Pike, Saline, Sevier and Union.

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Information from: Arkansas Democrat-Gazette, http://www.arkansasonline.com

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