A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
Crops > Vegetables > Lettuce > Leaf spots, lettuce, Kenya
June 2009. Leaf spots on lettuce from ?Kenya; what is it and how could it be controlled?
It was difficult to say much from the photo, but if the spots are zonate, it is possible that they are an Alternaria species. Look for velvety brown growth on the back of the spots.
The University of Florida sight says: Symptoms: Small circular spots are formed, the centers of which gradually dry and turn black. Production of spores increases the black appearance of the spots. Leaf lesions often exhibit a zonate appearance.
Rarely an economic problem in Florida; however, the use of maneb fungicides to control downy mildew on lettuce or endive will aid in control of this disease.