Beetles causing damage to trees

COLUMBIA - A little used but ecologically important tree is dying in droves along the Southeast coast because of an insect imported through the ports from Asia.


The redbay, which typically serves as lush greenery in the 15-25 foot height range in coastal forests, is being killed by the redbay ambrosia beetle - an Asian import that likely came to the states in redbay wood used in packing crates.

The first beetle showed up in traps at Port Wentworth in Savannah, Ga., in 2002.

This year, the beetles' handiwork is visible in South Carolina Hunting Island State Park. Volunteers counted 2,068 dead trees within 30 feet of the park's roads and trails in February, and experts worry the entire population could be wiped out.

Though the tree fits nicely between tall Sabal palmettos and ground-clinging saw palmettos, it has few uses.

Its wood is rarely used in furniture. Its leaf has many of the same qualities as bay leaves used in cooking, but most commercial bay leaves come from California and Mediterranean species.

The trees are used by landscapers because of their drought-tolerance, but they can easily be replaced.

"You don't really notice it because it's an understory tree, but it does add a lot of green to the forest," said Laurel Weeks, an interpretive program manager at Hunting Island. "It does fill a niche in the maritime forest. We don't know if something is going to come along to take its place." But as one of eight major tree species in coastal forests, the redbay plays a large role in the ecosystem, said Laurie Reid, an entomologist with the South Carolina Forestry Commission. Besides the birds and deer that feed on the leaves and small black fruit, the Palamedes swallowtail butterfly lays its eggs exclusively in the redbay.

Federal officials and forestry and agricultural scientists from South Carolina, Georgia and Florida have been monitoring the disease caused by the beetle in their states since 2004.

"We're trying to find out the biology of the beetle, find out where the beetle is and where it isn't," said Ms. Reid.

In Asia, the beetle attacks only stressed trees, but in the United States it has attacked healthy ones, too.

The disease spreads rapidly, and signs at Hunting Island ask campers not to take redbay wood off the island.


The Culprit: The redbay ambrosia beetle was first detected in the United States in a survey trap near Port Wentworth, Ga., in 2002. It is a small, elongated, cylindrical beetle about 2 mm long.

What it does: This ambrosia beetle introduces an unspecified vascular fungus into its host, causing infected redbays to wilt and die within a few weeks or months.

Damage so far: Limited to three counties in 2004, the beetle now is in 32. It spreads about 20 miles each year with no help.

What can be done: At this time there are no tested or proven treatments for prevention or control of this insect. To avoid spreading the beetle and pathogen to new areas, wood or chips from infested trees should not be taken out of the area where the trees were found.

Ecological importance: Redbay is important to wildlife because its fruit, seed and foliage are eaten by several species of songbirds, wild turkeys, quail, deer and black bear.

Economic importance: Very little impact, unless the disease spreads to other species of plants.