Leaf spots start as small, water-soaked to brown, circular spots about ¼ inch in diameter and develop a brown border and yellow halo plus target-like pattern of rings in the spot as it enlarges.
The Long Island Horticultural Research & Extension Center in Riverhead, NY added a new photo gallery to their Cucurbit Disease collection
for Alternaria leaf blight on cucurbits.
This disease is not considered an important disease of cucurbits, but can cause defoliation resulting in yield loss when left unmanaged especially during rainy periods or where overhead irrigation is used.
