You may have noticed your Eastern White Pines showing yellowing, browning, and loss of needles. While these symptoms may have become more noticeable in your area this spring, white pine needle damage (WPND) has been observed in the northern U.S. and eastern Canada – with increasing frequency and severity — over the past few years. The blight causes mature (one-year-old) needles to discolor and then drop off, which then creates a thinning of the tree crowns the following year.
Though research into this emerging problem is still ongoing, plant scientists believe it is likely caused by one, or perhaps a combination of a few, fungal pathogens that have been detected on damaged trees. Scientists further suspect that excessive spring rainfalls over several consecutive years created the conditions that caused these fungi to proliferate. Other climate-related factors, such as above-average winter temperatures followed by late-spring frosts, may have played a role in the blight.
Because the newly emerging, current-season needles appear to be undamaged on the affected trees, there has yet been no observed tree mortality from WPND. But the defoliation does weaken the pine, making them more vulnerable to other stressors such as drought and insects. Though not much can be done to prevent the premature needle loss, White Pine owners are encouraged to take measures to protect the trees from further stressors. Regular application of SavaTree’s 100% organic ArborKelp can help support the pines by stimulating new growth and fortifying root systems, and will help the trees better withstand the stresses of drought conditions and extreme temperatures.
For more information:
U.S. Department of Agriculture Forest Service, “Eastern White Pine Needle Damage,” http://na.fs.fed.us/pubs/palerts/white_pine/eastern_white_pine.pdf
Nicholas J. Brazee, Ph.D., of University of Massachusetts Extension, Plant Diagnostics Laboratory, “Dramatic needle browning and canopy dieback of eastern white pine (Pinus strobus) in southern New England,” June 2016, https://ag.umass.edu/sites/ag.umass.edu/files/content-files/alerts-messages/2016_white_pine_update.pdf
Needle fascicle of healthy Eastern White Pine