Little bug, big problems: Asian beetle threatens ash trees

The biologists had an idea they had an unpleasant something in the traps set in the ash trees at Agnes Scott College.

They were right. Their catch that July day: Agrilus planipennis, a little bug that poses a big problem for the state’s foresters. The insect, commonly called the emerald ash borer, is nearly always fatal to every variety of ash tree.

It’s denuded ash woodlands in the Northeast and Midwest, killing tens of millions of trees. It has one of the world’s renowned makers of athletic gear nervous. Hikers on the Appalachian Trail have walked through stands of dead ash trees, each a victim to an insect hardly a half-inch long.

Now, say scientists, the bug has been found in metro Atlanta: at a roadside in south Fulton County as well as at Agnes Scott in DeKalb County.

It won’t stop here, predicted James Johnson, chief of forest management for the Georgia Forestry Commission.

“It’s here,” Johnson said. “It’s going to spread.”

The ash borer hardly bears a second look. Iridescent green, with wings, it can easily fit on a penny. It joins other invasive species that have found rich pickings in Georgia. In recent years, foresters have documented wooly adelgids decimating hemlocks in North Georgia. In gardens across the state, farmers and homeowners are fighting a losing battle against kudzu bugs, which dine on ornamental and edible crops.

Like the kudzu bug and adelgid, the borer came from Asia. Scientists theorize it arrived in wooden pallets about a dozen years ago that entered the country through Detroit. The bug, which has no known native predators, has spread as far east as New Hampshire and has pushed west to Kansas.

The borer lays eggs on tree bark. The eggs produce larvae, resembling tiny maggots, that tunnel into the bark. For more than two years, they munch on the cambium, the cell layer that moves water and nutrients from roots to limbs. Few trees survive.

Scientists at universities across the Midwest are trying to stop the pest but have had limited success, Johnson said. Their best bet so far: a wasp whose offspring feeds on borer eggs.

The borers are a potential peril to an American icon, the baseball bat. Players from Ruth to McCann have relied on bats made of northern white ash.

Hillerich & Bradsby, which annually produces 600,000 Louisville Slugger bats from ash, has been watching the insect’s advance. The company makes bats from maple, too, but the majority are ash from forests in Pennsylvania and New York.

“I’ve been tracking them (borers) oh, for eight years or more,” said Brian Boltz, general manager of the division that cuts the bats and sends them to Louisville, Ky., for final touches. So far, he said, the insect has not shown up in forests where the best bat trees grow.

Ash trees make up about 1 percent of Georgia’s forests, but that doesn’t mean they lack a role in a woodland’s environmental health, said Malcolm Hodges, the director of stewardship for the Georgia office of the Nature Conservancy. The Georgia division helps protect about 320,000 acres across the state.

An ash tree, he said, provides a habitat for other creatures. “You lose a whole suite of things when you lose a tree,” he said.

In the meantime, the best thing Georgians can do to impede the borer’s progress is heed the state Department of Natural Resources, which urges people not to move wood from one region to another — especially firewood. Borers from one forest could migrate to another on the wood, said Kim Hatcher, a department spokeswoman.

The department operates 42 parks that offer camping, and nearly every one sells local firewood on-site, she said.

‘It’s an educational thing,” Hatcher said. “We make people aware of the consequences of bringing firewood from somewhere else.”

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