Woolly Adelgid Management in the Urban Forest

A comprehensive management program for urban hemlock, Tsuga canadensis (Carriere) under pressure of Tsugae adelges (Annand) is presented. Hemlock management includes assessment of hemlock condition noting HWA infestation and its impact to tree health, soil and tissue analyses, therapeutic intervention(s), and application of soil amendments to manage environmental stresses. The key to optimizing hemlock vitality is a proactive plant health program including early therapeutic intervention. In this study, hemlocks were assessed using several plant health parameters including on-site assessment of tree condition (size, percent infestation). Soil and tissue samples were taken for independent and in-house laboratory diagnostics. In-house diagnostics included measurement of change in shoot extension, estimate of percent chlorosis and needle shed, Munsell Color assessment, and needle dry weight. Therapeutic treatments for HWA suppression were applied using the Arborjet microinjection device.