PI(s): Salom, Scott M (Co-Project Leader), Kok, Loke T (Co-Project Leader)

Investigators: Snyder, Amy (Investigator), Herrick, Nathan (Investigator)

Abstract: Tree of heaven is an established weed tree from Asia that is invading disturbed habitats throughout much of the U.S. Two weevil pests of the tree in China are being imported and studied in quarantine. They are considered potential biological control agents for this weed pest.

Description:

The tree of heaven, Ailanthus altissima , is an introduced tree from Asia. It is now considered a pest because it colonizes disturbed habitats, overtakes native flora, and is extremely difficult to remove.  We initiated a biological control project in 2004, and are working collaboratively with the USDA Forest Service and the Chinese government to import two weevil species, Eucryptorrhynchus brandti (Harold) and E. chinensis (Olivier) that have been identified as important herbivores of this tree in China. Quarantine evaluations regarding rearing, life history studies, and host-range testing will be conducted. Additionally, we are conducting a survey on the herbivores associated with tree of heaven in Virginia.  In 2005 we studied the biology of E. brandtiand conducted some host-range testing experiments.  So far it appears that this potential agent is highly specific in its feeding choices. Quarantine evaluations regarding rearing, life history studies, and host-range testing are being conducted. Additionally, we are conducting a survey on the herbivores associated with tree of heaven in Virginia.  In 2005 we studied the biology of E. brandti and conducted some host-range testing experiments.  So far it appears that this potential agent is highly specific in its feeding choices.

Impact:

Because of the increasing encroachment of the weed combined with the difficulty in controlling it with cultural and herbicide-based tactics alone, biological control is an option that should be considered. If biological control agents can be found that reduce the reproduction and spread of the weed, it will be an important contribution toward the retention of native open-grown flora.