Publications /  Belgian technology contributes to developing-country food security:
The story of potato, the potential for sweetpotato

Spillover to sweetpotato

The ideal solution for a pest such as the sweetpotato weevil is to plant resistant varieties. Unfortunately, such resistant varieties have not been developed, despite efforts to select resistant clones in different parts of the world. Even where "less susceptible" varieties exist, they do not perform well under high pest population levels.

The African sweetpotato weevils, Cylas puncticollis and C. brunneus, are the most destructive pests of sweetpotato in Sub-Saharan Africa. Weevil damage renders them unfit for human and animal consumption and imparts a characteristic terpene odor to the roots. Crop losses due to weevil damage range from 20 to 80% of the harvest.

In other regions, where a different weevil occurs (Cylas formicarius), control of the pest is based on cultural practices, use of pheromones and bioinsecticides. In Africa, pheromones have not been effective against the sweetpotato weevil, and bioinsecticides are not generally available, nor affordable. The most promising direction for research is to develop true resistant varieties through the introduction of exogenous genes, such as the Bt gene, in order to confer resistance in sweetpotato.

Sweetpotato weevil attacks stems, crowns, and roots
of sweetpotato plants. Adults feed directly on leaves
and vines; larvae tunnel into the roots.