Leaf Scorch Tree Disease - Prevention and Control

Leaf Scorch Tree Disease - Prevention and Control Leaf scorch is a noninfectious condition caused by an unfavorable environment - there is no virus, no fungus, no bacterium to blame. It can not be helped by chemical control so you will have to discover the underlying causal factor which can be drying winds, drought, root damage and other environmental problems. Still, infectious diseases can attack the tree and make the condition even worse. Major target trees are Japanese maple (plus several other maple species), dogwood, beech, horse chestnut, ash, oak and linden. Symptoms Early leaf scorch symptoms commonly appear as yellowing between veins or along leaf margins. The problem is not often recognized during this early stage and can be confused with anthracnose. The yellowing becomes increasingly severe and tissue dies at leaf margins and between veins. This is the stage at which injury becomes easily noticeable. Dead tissue can often appear without any previous yellowing and restricted entirely to marginal areas and tips. Cause Scorch usually is a warning that some condition has occurred or is occurring that is adversely influencing the tree. It could be that the tree is not adapting to the local climate or has been given unsuitable exposure. Many of the conditions are the result of water not making it into the leaves. These conditions could be hot, drying winds, temperatures above 90 degrees, windy and hot weather following a long wet and cloudy period, drought conditions, low humidity or drying winter winds when soil water is frozen. Control When leaf scorch is noticed, leaf tissue has usually dried past the point of recovery and the leaf will drop. This will not kill the tree. Several steps can be taken to prevent more severe damage. Deep watering will help with moisture uptake. You need to make sure lack of water is the problem as too much water can also become a problem. Spring application of a complete fertilizer may help but do not fertilize after June. If the root system of a tree has been injured, prune the top to balance the reduced root system. Conserve soil moisture by mulching trees and shrubs with rotted leaves, bark, or other material.