Field of potatoes with severe late blight Tubers may be infected by P. infestans whenever sporangia and tubers come into contact, from early in the tuberization process until harvest. Infections most commonly occur when sporangia are washed from lesions on stems and foliage to the soil and then through the soil to tubers. Because sporangia can survive days or weeks in soil, tubers can become infected for a period of time after infections in the foliage are no longer producing sporangia. Field of potatoes completely destroyed by late blight. Piles of potatoes discarded owing to infections by P. infestans , followed by severe soft rot.
Tubers infected by late blight are especially susceptible to soft rot.
If some tubers in a crop are infected, store the crop in cool, dry conditions. Infections can probably also occur during harvest and subsequent handling. Although late blight inoculations during storage were previously considered highly unlikely, such occurrences have been documented recently. Tomato leaflet with late blight lesions. Tomato plants completely defoliated by late blight.