AVRDC International Cooperators'
Fact Sheet

Tomato Diseases


Gray Leaf Spot
Stemphyllum solani, S. lycopersici

Found worldwide in warm climates

small, circular gray leaf lesions


     

Damage Symptoms

Brown to black specks appear on both the young and older leaves. The lesions expand into 1 to 2-mm-diameter round spots that remain brown or develop a gray center. Lesions may be numerous causing leaves to turn yellow, then brown and drop. Defoliation can be severe.

Similar lesions may occur on younger stems and petioles. Fruits are not affected. 

 

spots, chlorosis, and blight on leaves

Spots, chlorosis, and blight on leaves

     

Conditions for Development

The disease is favored by extended periods of leaf wetness from rains or dew, and by moderate to warm temperatures. The pathogen can persist as a saprophyte or on alternate hosts such as other solanaceous crops and weeds.


Control

Many resistant cultivars are available. Fungicidal sprays may be used for susceptible cultivars. Recommended fungicides include Bravo (chlorothalonil) and Dithane (mancozeb).
 


Last updated: 2001. 
Information from:
Vegetable Diseases: A Practical Guide. Lowell L. Black, AVRDC; and AVRDC International Cooperators's Guide on Suggested Cultural Practices for Tomato.
 

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