Red pine scale is a scale insect native to Japan that feeds on red pine trees. Red pine scale nymphs settle down on a tree’s terminal end branches, feeding on sap and eventually causing the tree to die. It is thought that red pine scale is responsible for the historical loss of thousands in red pine trees across the Northeast, including the near complete loss of red pine in Maine.
However, due to the difficulty of detection and identification of the tiny insect, the extent that red pine scale was responsible for the historical tree loss is unknown.
Red pine scale was first detected in North America in 1946 in Easton, Connecticut, and on Long Island in 1950. In the couple of decades after it’s first New York detection, it was believed to have wiped out all red pine south of Westchester County. Red pine scale had never been reported in Upstate New York possibly because colder winter temperatures kept the populations low enough to remain undetected. Until now.
This June, DEC’s Forest Health Research Lab was contacted by a property owner in Hague, NY about dying red pine on Lenni-Lenape Island on Lake George. The property owner explained that the trees had died in under a year without any clear reasons as to why.
Upon arriving to the island, DEC staff noticed small, white clumps of “wool” at the base of needles and along smaller branches on the symptomatic red pine trees. DEC staff also noticed numerous dead and dying red pine back on shore across from the island.
In October, DEC visited a nearby red pine plantation in the Pharaoh Lake Wilderness Area. Many red pine appeared to be dead or dying with a white woolly substance around the base of needles suggestive of red pine scale. Samples were taken and sent along with specimens from the Lake George infestation to Cornell’s eDNA and Genomic Core Facility for DNA analysis. Both results came back positive as red pine scale.
It’s likely red pine scale is much more pervasive across NY’s landscape than previously documented. As New York’s winters continue to get warmer, red pine scale could continue to expand its range northward and cause red pine mortality in natural stands.
DEC’s Bureau of Invasive Species and Ecosystem Health plans to do extensive surveys in 2025 to determine the location and abundance of this invasive pest.
You can help in their efforts. If you see dead or dying red pine with “wool” around the base of the needles, please send photos and location info to foresthealth@dec.ny.gov.
More information about red pine scale can be found here.
Photo of Red pine scale provided by DEC.
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