and life cycle—Early blight
The early blight fungus can overwinter on potato refuse in the garden, in soil, on tubers, and on other
solanaceous plants. Infection occurs when spores of the fungus come in contact with susceptible leaves
and sufficient free moisture is present. Spore germination and infection are favored by warm weather and
wet conditions from dew, rain, or sprinkler irrigation. Alternate wet and dry periods with relatively
dry, windy conditions favor spore dispersal and disease spread. Tubers can be infected as they are lifted
through the soil at harvest. If sufficient moisture is present, spores germinate and infect the tubers.
blight can overwinter on tubers