TreeCare Industry Association

Late summer is a good time to look for potential problems in your customers’ landscapes. Early leaf color changes or drop, galls on external tree tissues, and caterpillar webs are three of the possible things that may be affecting your customers’ trees and shrubs. But before you start up the chainsaw and chipper in despair, recognize that not all stress symptoms are a death sentence for the plant. Early Leaf Color Changes. We look forward to a good fall foliage color display in October and November, but what if those colors appear early—in August or September? Premature color change can be an indication that a tree is lacking the vigor to withstand insects and disease organisms that may attack it—or there could be environmental imbalances as well. Heat, drought, and drying winds affect trees, causing leaf color changes as a response to stress. Are there only one or two branches affected? This could be a sign of a disease at work, especially if the affected leaves also have dark spots or are discolored. The more common situation is for the entire tree to exhibit premature fall coloration, a phenomenon usually linked to root-related stress. And to complicate the diagnostic process further, there are several tree species genetically programmed to go dormant during hot summer months and drop browning, curled leaves in response to heat stress. The best way to counter early leaf stress symptoms is to know which tree species you are working with. Are those curled, brown leaves on ...