Fusarium causes stem rot and can decrease yields or even kill plants of certain varieties. Other diseases attack only the surface of the sweet potato. Surface diseases affect appearance but not eating quality. Storage diseases can be minimized by proper aeration and storage conditions, and avoiding injury to the roots. Nematodes and soil insects are of minor importance to the home gardener.
Nematodes can cause misshapen, cracked, and galled roots as well as decreased yields.
Use resistant varieties for the specific nematode present. No chemical control is available. Leaf-feeding beetles rarely pose a threat to sweet potato yields, but if serious damage occurs, you can control them easily with an insecticide. Soil insects affect sweet potato roots. However, most damage is not deep and can be cut away with a knife before cooking.