Beetle from Australia threatens eucalyptus

S i n c e the eucalyptus longhorn borer was discovered in October 1984 infesting eucalyptus trees near El Toro, California, it has been spreading rapidly in the southern part of the state. Subsequent surveys (February 1986) by state and county agencies have found the borer along the coast from Long Beach to San Diego and inland to Van Nuys and Hemet. Eucalyptus has been planted in California since the 1860s but has been free of major pests until the arrival of the borer, Phoracantba sernipunctata (Fab.), a cerambycid beetle. The borer is the first such pest to reach the United States from Australia, the native home of eucalyptus. In Australia, this beetle occurs throughout eucalyptus forests, but its damage is usually restricted to dead and dying trees. During severe droughts, beetle outbreaks may occur, but its populations normally appear to be limited by a complex of natural enemies, including predators and parasitoids. Eucalyptus has also been planted in several other countries, including Israel, Morocco, Spain, and South Africa, where the wood is used for lumber, paper pulp, telephone poles, mine supports, and fuel. The eucalyptus longhorn borer has been accidentally introduced into many of these countries, and is killing trees and severely damaging logs intended for structural timber and telephone poles. One of the more common broadleaf trees in urban California, eucalyptus is potentially threatened by the beetle in Healthy eucalyptus trees respond to Phoracantha larval boring by producing copious quantities of gum that smother the larvae.