Some trees that harden off gradually in the fall can take temperatures as low as 0 degrees F and show no damage. Other individuals are hurt easily if temperatures commonly get below 15 degrees F. Killing of leaves and shoots can be extensive. Winter drought coupled with low temperatures can cause extensive die back or death. In rainy seasons this disease may be serious on silver maples and Japanese maples. Many spots occur along the veins.
Areas often enlarge killing the entire leaf.
Leaves partially killed appear as if scorched. Many infected leaves drop in late spring. Twigs may die back. Collect and destroy fallen leaves. Spraying with a recommended fungicide when buds begin to unfold in the spring and again in 10 to 20 days will help prevent infection.