Efficacy of arborjet viper microinjections in the management of hemlock woolly adelgid

Abstract

Hemlock woolly adelgid (Adelges tsugae Annand) is an introduced homopteran that infests native eastern hemlock (Tsuga canadensis Carriere). It results in reduced tree vitality and, when untreated, death. A state-of-the-art microinjection device employing an air-over-hydraulic system was used to deliver a therapeutic dosage of imidacloprid into the active xylem tissues of affected hemlocks. Bioassays were conducted microscopically to determine HWA mortality post-treatment. Injected trees had significantly (p < 0.05) lower HWA populations compared to untreated controls; mean mortality for injected trees was over twice that of noninjected trees. The Arborjet VIPER system shows promise as a management tool in the treatment of HWA.