Pythium ultimum and other spp.s Symptoms Dark lesions that spread on and within the tuber and quickly turn to soft rot. A foul odor becomes apparent as other microorganisms begin to develop. Damage Complete rotting of the tuber during harvest and storage. Tubers are unusable for propagation.
Most inoculation occurs during the growing season, harvest and grading.
If there has been no treatment administered for late blight, systemic fungicides may be applied at the end of the growing season. Soil fumigation may eradicate the pathogen in the soil. Proper drainage in the field, preventing delay of harvest, taking care not to wound tubers, keeping the storage area well ventilated.