Methods for collecting and rearing three sympatric biocontrol agents of Adelges tsugae (Hemiptera: Adelgidae) in eastern North America.

Abstract

A decline in global forest health, due in part to the spread of insect pests, has prompted research into effective, sustainable, and economically feasible solutions to manage forest pests, including the use of classical biological control. Among the top 5 imperiled tree species in North America, eastern hemlock (Tsuga canadensis (L.) Carriere) is impacted by the invasive hemlock woolly adelgid, Adelges tsugae Annand, accidentally introduced from southern Japan. Three specialist natural enemies of A. tsugae found on western hemlock woolly adelgid in western North America have been deemed promising biological control agents and approved for release-2 species of silver fly, Leucotaraxis argenticollis (Zetterstedt) and Leucotaraxis piniperda (Malloch), and a beetle, Laricobius nigrinus Fender. Supplying quantities of these predators needed for research and release has special challenges given their dietary and habitat needs. We have developed novel collection and rearing methods for producing these 3 predators simultaneously in large numbers as part of a rearing and release strategy in eastern North America.