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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Lettuce : Aster yellows
(revision date: 6/3/2014)


Biology
Aster yellows is caused by a phytoplasma which is a microorganism found in the phloem tissue of a plant. The phytoplasma is spread by leafhoppers and can also affect carrot, onion, potato, celery, and other crops, weeds, and ornamentals. Initial symptoms are seen on young leaves in the heart of the plant. These leaves turn yellow and may fail to develop normally, resulting in a thickened, stubby appearance. Affected leaves show characteristic pinkish or tan latex deposits on the underside of the midribs. Young plants may show yellowing of the outer leaves and severe stunting, while older plants may show only internal symptoms and the latex deposits.
Management Options

Non-Chemical Management
  • Control weeds in and around the garden.
  • Control leafhoppers.
  • Since leafhoppers tend to avoid shaded plants, shading lettuce may help reduce the risk of infection.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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