These blemishes contain dark-colored spore balls that spread beneath the epidermis and erupt when the tuber emerges. In severe cases, the tubers are malformed and covered with unattractive secondary growths. If the plant is also infected with mop top, which can be transmitted by the fungus, deep cracks appear. Roots may also be affected with gall formation. Damage Severe malformation of the tubers.
Spores can survive in the soil for years.
Contaminated propagation material is unusable. Penetration occurs through the open lenticles. Tomato and other solani spps can also serve as hosts and infest the soil. The spores survive in the digestive systems of animals. According to the literature, disinfesting tubers with caspan or formaldehyde effectively controls the pathogen on the seed tubers.