Chautauqua Watershed Conservancy has been conducting yearly Hemlock Woolly Adelgid (HWA) surveys on our preserves and other local hemlock stands for over a decade.

HWA is a very small insect that feeds on hemlock trees, ultimately killing the infected trees. These invasive adelgids are transferred from tree to tree most often by birds, but other modes of transmission are possible as well. Once the adelgids land on the host tree, they will remain in the same spot for the rest of their lives, continually feeding and developing into adults. Their feeding severely damages the canopy of the host tree by disrupting the flow of nutrients to its twigs and needles, and the infected tree usually dies in four to ten years.

Our surveys take place in January through mid-March since HWA is most visible in winter. In the coldest months, the aphids go dormant and form cotton-like protective balls at the bases of hemlock needles, making it easy to observe and diagnose. This dormant period also makes it much less likely for surveyors to accidentally spread HWA from tree to tree by physically touching multiple hemlocks in an area during a survey.

HWA is moving into our area very quickly. By surveying local hemlock trees and reporting any HWA we observe on them, we can help with the implementation of targeted treatment plans to manage the infestations and prevent further spread.

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Read more at https://www.chautauquawatershed.org/post/local-trees-are-calling-for-help