Sweet potato rust

Sweet potato rust is a fungal disease caused by the pathogen Puccinia batatae. As an obligate biotroph, this fungus strictly requires living host tissue to complete its life cycle and obtain nutrients, which often results in severe physiological stress for the infected host plant.

The primary host for this pathogen is the sweet potato (Ipomoea batatas). While it can be found in various regions where sweet potatoes are cultivated, the disease is particularly prevalent in areas characterized by high humidity and consistent moisture, which are critical for the fungus's reproductive phase.

The visual symptoms typically appear as small, chlorotic spots on the upper leaf surface, followed by the development of characteristic reddish-brown pustules on the underside of the leaves. These pustules represent the fruiting bodies of the fungus, which release spores that facilitate the secondary spread of the disease throughout the field.

The development and spread of Puccinia batatae are highly dependent on environmental conditions. Extended periods of leaf wetness and mild to warm temperatures accelerate spore germination and colonization. Wind and splashing rain are the primary vectors for dispersing spores from infected foliage to healthy, susceptible tissues in the crop.

The economic impact of sweet potato rust is significant due to the reduction in photosynthetic efficiency, which directly leads to smaller tuber size and reduced overall yield quality. Effective disease management strategies include the following actions:

• practicing crop rotation to break the pathogen's cycle;
• sanitation measures, such as removing and destroying infected plant debris;
• selecting resistant or tolerant sweet potato varieties;
• applying appropriate fungicides when the disease pressure is high.