Operation adelgification: evaluating a rain down technique to artificially infest seedlings with the hemlock woolly adelgid

Over the last two decades, the hemlock woolly adelgid (HWA, Adelges tsugae Annand) has caused widespread mortality among populations of Eastern (Tsuga canadensis (L.) Carriére) and Carolina (Tsuga caroliniana Engelmann) hemlock throughout the eastern United States. The integrated strategy to manage the impacts of this invasive insect pest on eastern forests includes biological control, chemical insecticides, silvicultural practices, and gene conservation. During the last nine years considerable progress has also been made in understanding hemlock-adelgid host-insect interactions and the potential for breeding hemlocks resistant to HWA. Operational programs for selecting and breeding hemlock genotypes that express resistance characteristics will require infesting large numbers of hemlock seedlings with HWA, and techniques for doing this in a consistent and reliable manner are currently lacking. Our poster presents the results of a pilot study designed to address this topic through the use of a rain down technique for artificially infesting seedlings with adelgids. We report the distribution and abundance patterns and hemlock seedling infestation rates of adelgid progrediens and sistens crawlers (first instar nymphs) raining down inside cubic (1m x 1m x 1m) pvc cages.