Science / Medicine : Australian Wasp Released

Researchers at UC Riverside have begun releasing an imported wasp they hope will hold in check an imported pest that is devastating eucalyptus groves in Southern California. The eucalyptus longhorn borer beetle, whose natural habitat is Australia, was first detected in Orange County in 1984 and has subsequently spread north to Ventura, east to the Imperial Valley, and south to Mexico. Larvae of the beetle drill beneath the bark of the trees and kill those that are already diseased or that have been weakened by heat or drought.

The wasp, called Syngaster lepidus, is also an Australian native. The wasp uses its stinger, which is as much as an inch long, to drill through eucalyptus bark and paralyze the larvae. It then deposits eggs that hatch into wasp larvae that feed on the paralyzed beetle larvae. If the imported wasps successfully control beetle infestations on the Riverside campus, the researchers will transfer wasp cocoons to other infected areas.