Interactions between the Matsucoccus scale insect/pathogen complex and eastern white pine health in the southern Appalachian Mountains

We are assessing the extent, severity, and nature of eastern white pine (Pinus strobus) health issues in the southeastern U.S.  White pine trees (all diameter classes) appear to have high densities of cankers on branches and main bole, branch flagging, and crown thinning in the southern Appalachians. Mortality of both young and mature white pine is occurring in multiple states including Georgia, Virginia, and West Virginia. Associated with the cankers is a novel and previously unreported complex of a pine bast scale, Matsucoccus macrocicatrices and multiple fungal pathogens.  Matsucoccus macrocicatrices has previously not been reported or collected from the Southeast, or found associated with tree dieback/mortality and pathogens. Preliminary results from monitoring of 11.4 m radius plots established in three states indicates that 100% of white pine are symptomatic with 41% dead trees. The percent of necrotic nodes per sapling increased within a year by 50%. Most of the mortality is occurring in smaller diameter trees (<30 cm) with larger diameter trees symptomatic as well. Current work is focusing on assessing the interactions between the scale insect and fungal pathogens, their relative impact on tree health, and phenology and genetics of the scale insect in eastern U.S.