WSU Extension

Hortsense

Lettuce
 
Disease
Anthracnose 
Aster yellows 
Beet western yellows virus 
Bottom rot 
Damping-off 
Downy mildew 
Lettuce big vein virus 
Insect
Aphids 
Slugs 



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Caption: Lettuce anthracnose
Photo by: R.S. Byther
  
Lettuce : Anthracnose
(revision date: 6/3/2014)


Biology
Anthracnose of lettuce is a fungal disease favored by cool, wet weather. The disease is also known as shothole because of the characteristic symptoms. Lower leaves develop small, water-soaked spots which quickly darken and enlarge. The centers dry and drop out, leaving "shotholes" with black margins in the leaves. Affected leaves tend to wither and die quickly, then break off. The disease progresses to the younger leaves and may also cause symptoms on the midribs. The fungus is spread by splashing water and can be serious during prolonged wet weather. Some weed species are also hosts of the fungus.
Management Options

Non-Chemical Management
  • Control weeds in and around the garden.
  • Remove plant debris from the garden. Destroy or discard (do not compost) infected materials.
  • Rotate crops. Do not plant lettuce in the same location each year.
  • Avoid overhead watering.
  • Remove affected plants as soon as symptoms are noticed.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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Caption: Lettuce anthracnose
Photo by: R.S. Byther
Caption: Lettuce anthracnose
Photo by: R.S. Byther