WSU Extension

Hortsense

Madrone
 
Disease
Collar rot (Phytophthora) 
Leaf blight 
Leaf gall 
Leaf spot 
Madrone canker 
Insect
Madrone leafminer 
Shield bearer 



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Caption: Leaf blight on madrone in OR, March 2011
Photo by: G. Chastagner
  
Madrone : Leaf blight
(revision date: 4/28/2014)


Biology
Madrone trees suffer from numerous fungal leaf diseases. One such problem, madrone leaf blight, appears to be caused by a pathogen that damages leaves after periods of cold weather in winter or early spring. Affected leaves develop brown spots which coalesce and form large blotches. The damage is worse where water collects (on the tips and edges of leaves and in the lower part of the canopy). Heavily-infected leaves may turn completely brown, sometimes throughout the entire canopy. Damaged leaves usually remain on the branches for several months, finally dropping off at the end of the following summer. New leaves emerging in the spring typically do not show symptoms of leaf blight. Young or stressed trees may be more severely affected than mature, healthy trees. Little is currently known about the long-term effects of this blight, though repeated loss of leaves will likely affect plant vigor and survival. Leaf blight on madrone should not be confused with other fungal leaf spot problems, which typically cause only minor damage. See also Madrone: Leaf spot.
Management Options


Non-Chemical Management
  • Until more is known about fungal leaf blight on madrone, good sanitation practices should be used when practical. Clean up and dispose of fallen blighted leaves around valuable landscape trees.
  • Avoid stressing madrones with poor planting location or improper culture. They prefer native soils with excellent drainage, grow best in full or partial sun, and can tolerate poor soils.
  • Good air circulation is important since fungal diseases are more severe in crowded, humid conditions.
  • Do not irrigate established trees, as they are adapted to summer drought.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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Caption: Leaf blight on madrone in OR, March 2011
Photo by: G. Chastagner