Comparison of Numerical Response and Predation Effects of Two Coccinellid Species on Hemlock Woolly Adelgid (Homoptera: Adelgidae)

摘要: The hemlock woolly adelgid, Adelges tsugae Annand, is an introduced pest in North America that native to Asia, and causing extensive damage eastern (Tsuga canadensis Carriere) Carolina caroliniana Englemann) the United States. We compared two coccinellids imported for biological control of adelgid: Scymnus ningshanensis Yu et Yao from China Pseudoscymnus Sasaji McClure Japan. In a laboratory study, we measured numerical response each beetle species range prey densities, field studies examined reproductive success ability reduce populations adelgid. laboratory, S. showed positive as adelgid density increased, P. density-independent response. cages, presence resulted negative population growth, contrast growth both cages containing tsugae. Both our experiments suggest has good potential agent