Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, May 11, 1993 TAG: 9305110021
SECTION: CURRENT PAGE: NRV1 EDITION: NEW RIVER VALLEY
SOURCE: ROBERT RIVENBARK SPECIAL TO THE ROANOKE TIMES & WORLD-NEWS
DATELINE: BLACKSBURG LENGTH: Medium
The newcomer is a beneficial insect that feeds on harmful aphids that suck the sap from garden plants and fruit trees.
Eric Day, state survey coordinator and manager of Virginia Tech's Insect Identification Laboratory, said the beetles turned up in January in a Lee County modular home made in Alabama. Paul Chambers, extension agent for Russell County, collected one from his daughter in Lee County and sent it to Day.
Day identified the beetle as Harmonia axyridis, a native to Japan, China and Siberia. Paul Shaefer of the U.S. Department of Agriculture's Beneficial Insects Introduction Laboratory in Newark, Del., confirmed Day's identification.
Shaefer said his laboratory imported Harmonia axyridis from Japan in the mid-1970s and set them loose in Georgia and Mississippi to control aphids on pecan trees. The lab also introduced the beetle into Maine and the Yakima, Wash., area to control spruce and apple-tree aphids.
Follow-up checks conducted in the years after the introductions turned up no specimens. Shaefer and his associates thought the beetle had failed to adapt and had died out.
In the early 1980s, however, Harmonia axyridis unexpectedly turned up in southeastern Louisiana, Shaefer said, apparently having been brought into New Orleans accidentally in cargo from the Orient.
Since its Louisiana appearance, the beetle has turned up in Mississippi and Georgia and more recently in North Carolina. Since the Virginia sighting in January, the beetle has been seen in West Virginia, too.
Shaefer wouldn't speculate about whether the northern migration of the beetle has come about as a result of accidental introduction into Louisiana, or from his laboratory's deliberate introductions into Georgia and Mississippi in the '70s.
In either case, the recent sightings show Harmonia axyridis has developed a taste for North American aphids, something gardeners and fruit-tree growers can celebrate, Shaefer said.
After hibernating for the winter in rock outcroppings or in the bases and cracks of houses, Harmonia axyridis emerges in early spring to hunt for aphid eggs growing in fruit trees and common shrubs. After the aphids hatch from their colonies in late spring, the beetles attack the adults.
Harmonia axyridis' success may be bad news for native ladybug beetles, which could be displaced by the newcomers.
" Harmonia axyridis seems to be more successful than native ladybugs in finding aphid colonies," Shaefer said. "They just seem to be a little better searcher and are better at finding prey."
by CNB