Hemlock Wooly Adelgid
The Ohio Department of Natural Resources describes young hemlock wooly adelgid as crawlers. The crawlers move to a location on a twig of either an Eastern Hemlock and begin feeding. Young adelgids then cover themselves with a white wooly substance and continue to develop until maturity. Adult adelgids are black, around 2 mm long and are all females.
Management for adelgids can vary, they include chemical treatments, tree removals and biological controls. All three are currently being used throughout Ohio. Chemical treatments for adelgids include applications of insecticides through soil drenches, tree injections, and basal bark treatments. Trees removal is generally used in small, isolated populations, or where chemical treatments are not practical. At times, tree removal and chemical treatments are done in the same habit to increase control of adelgids.
Preventative measures are focused on keeping materials from transporting adelgid to non infected areas. According to the Ohio Department of Agriculture, Ohio quarantine regulations restrict the movement of hemlock materials from counties known to be infested into non-infested Ohio counties. The law also requires hemlock materials grown in non-infested counties in quarantined states to be inspected before being shipped and have a phytosanitary certificate verifying that the plant material is free of HWA when entering Ohio.
The hemlock woolly adelgid causes damage to trees through feeding on the sap and nutrients from the hemlock foliage and depleting its reserves. The Ohio Department of Agriculture says tree can die within four to five years depending on the health of the tree at time of infestation and secondary causes that come into play as the tree is weakened.
Tree mortality can cause a dramatic shift in the composition of forest species, both plant and animal, and can affect the ecological processes that occur such as nutrient cycling, decomposition, leaching, stream temperatures and stream organisms. The damage to these trees can lead to a shift in the whole ecosystem.
