Due to this year’s excessively wet spring, we are currently seeing two moisture born diseases throughout the Boston region, including Framingham. Rhytisma Acerinum or “Tar spotting” and Anthracnose are both minor diseases that can cause black spots and early, partial defoliation. Norway Maples and Crimson King Maples that have been historically planted as street trees are often the most frequently affected tree species. The diseases are not life threatening and we expect the trees remain in good health.
We do suggest that you collect and bag the fallen leaves to help prevent the spreading of these diseases. This will also curb proliferation of the diseases next season. Watering will help keep trees healthy if performed at the rate of one inch per week. The best time to water your trees is in the morning. Night time watering can help feed the fungi which are causing the disease.