Air pollutants

Air pollutants cause dark lesions
on leaves that resemble late
blight but no yellowish halo
surrounds the lesions No white
fungal growth develops in wet
weather as in late blight lesions
Acid rain lesion

Tipburn

The tips of leaflets turn brown

Heat stress

Brown areas on leaflets develop when hot weather
prevails for several days
author avatar
T.G. Lynn