Mapping the distribution of a potentially new tiny terror in southern white pine forests

Eastern white pine (Pinus strobus) is an ecologically and economically important conifer tree species found across the eastern region of North America. Recently, white pines in the southeastern U.S. have started showing signs of dieback with multiple canker formations and pitching. A closer investigation revealed that a scale insect, Matsucoccus macrocicatrices, is associated with the cankers.  The scale insect is typically found under lichen, epiphytic mats or branch crotches and is often associated with cankers. Since white pine dieback has become more prevalent, it is critical to assess its health in the southeastern U.S.

Our objectives are to: 1) determine the range and severity of dieback of symptomatic white pine trees in the southern Appalachians; 2) assess if white pine health varies based on different site conditions; and 3) begin to determine the correlations between the scale insect, fungal pathogens, cankers and health of eastern white pine.

To determine the range of dieback in the southeastern U.S., we have established 40 sites (three plots per site) across six states (GA, NC, SC, TN, VA and WV). Within each plot, we are sampling for basal area, topographic features, and assessing the overall health of white pine trees. Additionally, white pine saplings were collected and analyzed to establish correlations between the white pine trees, scale insect and cankers for each site. The results of this study will update the distribution of the scale insect, and shed light on any tree/insect/canker interactions.