Cankers and galls (viral)

The primary host for this fungus is the potato. It affects tubers, stolons, and the basal stems of the plant. While other nightshade species can sometimes host the fungus, the potato is the only crop where the infection results in significant agricultural damage and the formation of characteristic wart-like galls.

The hallmark symptom is the formation of irregular, fleshy outgrowths on tubers. These growths start as small bumps and expand into large, warty structures resembling cauliflower or coral. Eventually, these galls darken, decay, and release resting spores (sporangia) into the surrounding soil, ensuring the persistence of the pathogen.

The disease thrives in cool, moist soil conditions. The resting sporangia are incredibly resilient, capable of surviving deep in the soil for up to 30 years or more. Spread occurs primarily through the movement of infested soil, contaminated farm machinery, manure from livestock fed with diseased tubers, and the transport of infected seed potatoes.

Management focuses on strict containment and prevention. The most effective strategy is planting resistant or immune potato cultivars. If an outbreak occurs, affected fields must be quarantined, and equipment must be thoroughly disinfected. Chemical control is limited and generally impractical, making crop rotation and the use of resistant germplasm the cornerstones of successful disease management.