Published on 04/07/97

Ambrosia Beetles Not Nectar From the Gods

Do trees in your landscape look like toothpick holders at restaurants? If so, they may be under attack by Asian ambrosia beetles, which aren't exactly nectar from the gods.

"Ambrosia beetles are small wood-boring beetles that are really giving us fits in Georgia," said Will Hudson, a University of Georgia Extension Service entomologist. "We've had serious losses all across the state, from Cairo to Blairsville."

The earliest signs of infestation have been in nursery stock. "One nursery reported losing more than 150 Bradford pear trees already," Hudson said.

At around $20 per tree, wholesale, that's an expensive problem. While the final tally hasn't been made for this year, Hudson expects damage and losses to be in the "many thousands of dollars" range.

"The beetles carry a type of fungus that infects the tree," Hudson said. "A young tree that has been attacked will usually die."

Ambrosia beetles are also undiscriminating creatures.

"They attack hundreds of different trees -- really any kind of deciduous tree or shrub can be in danger," he said.

Besides being voracious and undiscriminating, ambrosia beetles are also hard to control.

"That's the problem," Hudson said. "What we've been doing for normal borer treatment isn't successful for this beetle. We don't have a solution to offer for this beetle. The nurserymen are watching very closely -- that's how we know the extent of the problem."

When you're buying trees, or if you have young trees in your landscape, look for tiny holes the size of a pencil lead in the bark.

"Usually there will be a piece of sawdust that looks like a toothpick sticking out, but a good wind can blow that away," Hudson said.

If you suspect that you have an infested tree, contact your county agent for a proper diagnosis.

"We don't have a solution for ambrosia beetles once they're in the tree," Hudson said. "They're in the heartwood and aren't going to be susceptible to treatment. You should expect that the tree will die."

Many homeowners are reluctant to cut a tree down until it's dead, but if you have ambrosia beetles, be prepared for it to die.

"Call your county agent before you cut a tree down," Hudson said. "Other beetles bore into trees -- perhaps you'll be lucky and not have the Asian ambrosia beetle."

Faith Peppers is the director of public affairs with the University of Georgia College of Agricultural and Environmental Sciences.