Quarantine evaluation of Eucryptorrhynch us brandti (Harold) (Coleoptera: Curculionidae), a potential biological control agent of tree of heaven, Ailanthus altissima, in Virginia, USA

摘要

Tree of heaven, Ailanthus altissima (Mill.) Swingle, is an imported invasive weed tree from China that has become established throughout much of the continental USA. It colonizes disturbed forest sites and often out-competes native vegetation. Short-term cultural and chemical controls of this weed are expensive and have limited efficacy. Eucryptorrhynchus brandti (Harold) and Eucryptor-rhynchus chinensis (Olivier), two curculionid species, are pests of A. altissima in China and have no other known hosts. The objectives of our project are to (1) assess the pest status of A. altissima in Virginia and (2) evaluate E. brandti for its potential as a biological control agent. A statewide survey showed significant presence of tree of heaven but no native herbivores with potential of controlling it, suggesting biological control to be an attractive method of management. As E. brandti requires live trees for development, quarantine studies have focused on developing a rearing technique and testing the hostspecificity on native plants approved by the Technical Advisory Group for Biological Control Agents of Weeds. Preliminary results indicate that E. brandti feeds only on tree of heaven, with greatly reduced feeding observed on corkwood, Leitneria floridana Chapman, and paradise tree, Simarouba glauca DC.