Alternaria
Leaf Spot (fungus - Alternaria cucumerina): Small, circular watersoaked
spots first appear on the leaves, later enlarging to one and one-half inch or
more in diameter. Definite concentric rings and margins appear giving the diseased
area a "bull's eye" appearance. The fungus overwinters in crop residue and on
other cucurbit plants. Numerous air-borne spores are produced on diseased spots.
Crop rotation and seed treatment help. A preventative fungicide
program should be followed when the disease occurs consistently.
