WSU Extension

Hortsense

Oak
 
Disease
Anthracnose 
Armillaria root rot 
Leaf scorch 
Mistletoe 
Sudden oak death 
Insect
California gallfly 
Jumping oak gall 
Leaf galls 
Oak leaf phylloxera 
Oak ribbed casemaker 
Oak treehoppers 
Pit scale 
Stem galls 
Western oak looper 



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Caption: Leaf scorch on oak
Photo by: B.M. Johnson
  
Oak : Leaf scorch
(revision date: 4/28/2014)


Biology
Leaf scorch has many possible causes. Plants that are under stress (such as from drought or heat) may not provide sufficient water to leaves, causing the edges to turn bronze, then later brown and dry. In severe cases, the scorch may spread to areas between veins or entire twigs may die back. Trees placed near heat-reflecting surfaces such as buildings or pavement often suffer from heat stress. Other possible causes of scorch include damage to roots or stem, soil compaction (which can cause reduced drainage resulting in root damage), or the presence of excessive salts from overuse of chemical fertilizers.
Management Options


Non-Chemical Management
  • Irrigate affected plants during dry periods. Wet the entire root zone, but do not overwater. Try to water oaks deeply but infrequently.
  • Do not overfertilize.
  • Avoid injury to roots and trunk.
  • Heavy foot traffic, construction, and heavy equipment can cause soil compaction and root damage.
  • Do not plant trees directly against the sunny sides of buildings.
  • Do not pave over the root zone of established trees.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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Caption: Leaf scorch on oak
Photo by: B.M. Johnson
Caption: Leaf scorch on oak
Photo by: B.M. Johnson