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close this bookBetter Farming Series 16 - Roots and Tubers (FAO - INADES, 1977, 58 p.)
close this folderSweet potatoes
close this folderHow to grow sweet potatoes
View the document(introduction...)
View the documentPropagation of sweet potatoes
View the documentLooking after the plantation
View the documentYields of sweet potatoes and storing

Looking after the plantation


One or two cultivations in the early stages of growth are enough. In 4 to 6 weeks after planting, the plant's own leafy growth will closely cover the soil.

When cultivating, remake the mounds at the same time.


Sweet potatoes attacked by diseases and insects yield only a small harvest of poor quality.

You must wait 3 to 5 years before growing sweet potatoes again on the same field.

- Rot and fungi

Diseases that kill the growing plants are caused chiefly by various fungi. Some fungi make the leaves turn yellow and wither. Other fungi make the stems or tubers rot. Signs of the disease are yellow leaves and black marks inside the stems and tubers.

Other fungi cause the young plant to rot. It stops growing. The roots and the tubers already formed turn black. It is not long before the whole plant withers and dies.

To control most forms of rot, you must choose resistant varieties. Do not use for propagation cuttings or tubers taken from plantations attacked by rot.

Do not grow sweet potatoes on the same soil 2 years in succession.

- Insect pests

Sweet potatoes may be attacked by certain insects, especially by weevils.

The adult insects eat the leaves, stems and tubers. The female insects lay their eggs in the stems or roots; the larvae tunnel into the tubers. Serious damage is caused by weevils.

To control the weevils, use insecticides. Before planting tubers and cuttings, dip them in a solution of Dieldrin.

In places where harvested sweet potatoes are stored, they can be fumigated with phostoxin in tablets.