What is sweet potato pox? Learn more about sweet potato soil rot
If your sweet potato crop has black necrotic lesions, it may be sweet potato pox. What is sweet potato pox? Sweet potato pox is a serious disease of cash crops that is also known as soil rot. Sweet potato soil rot occurs in the soil, but the disease progresses when the roots are stored. Fields that have been infected cannot be planted for many years. This results in economic losses and reduced yields. Know the signs and symptoms of this disease to prevent its spread.
Information about sweet potato soil rot
Sweet potatoes are a high source of vitamins A and C, and are one of the largest crops in the southern United States. China produces half of the world’s sweet potatoes for consumption. The root has become popular as an alternative to traditional potatoes because of its high nutrient and fibre content.
Sweet potato diseases, such as smallpox, cause millions of dollars in economic losses. In the home garden, such infections can render the soil unusable. Good sanitation practices can help prevent sweet potato rot in the soil.
Signs of infection on the surface are yellowing and wilting of the plants. In extreme cases, plants may even die or not produce tubers. The tubers themselves develop black, crusty lesions, are deformed and have bumps in some places. The fibrous feeder roots rot at the ends, interrupting plant uptake. The underground stems will also become black and soft.
Sweet potatoes with soil rot have characteristic corky lesions. If the disease progresses, the tubers become inedible and the plants die. The pathogen causing all these problems is Streptomyces ipomoea.
Conditions for sweet potato pox
Once we have answered the question of what smallpox is, we need to know when it occurs and how to prevent it. The most common conditions that favour the disease are increasing soil pH above 5.2 and light, dry, grassy soils.
The pathogen survives for years in the soil and also infects morning glory weeds. The pathogen can spread from field to field with contaminated material. It can also spread when infected tubers are used as grafts to start new plants. The disease can even survive in stored sweet potatoes and infect a field if it is later used as seed.
Prevention of sweet potato pox
The rotting of sweet potato soil can be prevented by measures and tricks. The easiest way to avoid soil contamination is to adopt good sanitation practices. Decontaminate all hand and power tools before moving them to another area. Even the floor or storage boxes can harbour disease.
Crop rotation can help prevent the movement of the pathogen, as can soil fumigation. Probably the best control method is to plant resistant sweet potato varieties. These could include Covington, Hernandez and Carolina Bunch.
Soil pH control can also be useful when it is possible to obtain management to prevent the pH from becoming too acidic. Incorporate elemental sulphur into soils with a pH above 5.2.
