مرض فطري يسببه الفطر Alternaria solani وله نفس الأعراض وطرق العدوي والمكافحة المبينه في مرض اللفحة المبكرة في الطماطم
الأعراض الأولي علي الورقة
الأعراض علي الدرنة وهي نادرة الحدوث
Cause: Alternaria solani, a fungus that overwinters as viable mycelium and spores in infected crop residue. Heavy dews and frequent rains seem essential for severe outbreaks. The disease is found primarily under sprinkler irrigation.
Symptoms: First, oval or angular dark brown to black "target" spots appear on leaflets. Usually a narrow chlorotic zone is around the spot which fades into the normal green. Lowest, oldest leaves are infected first, and they droop and dry as the disease progresses. If spots are numerous, they kill leaves and consequently may reduce yield.
Tuber infection is less frequent than leaf infection. Tuber lesions are sunken spots, brown to black, from 0.12 inch to 0.37 inch in diameter, and normally circular. The margin between diseased and healthy tubers is usually quite well defined. Underlying tissue shows a brown, corky, dry rot more than 0.12 inch deep.