Although sweetpotato can be produced under difficult growing conditions, weevils and other nematode and insect pests continue to plague production despite the use – and misuse – of insecticides.
The best strategy to counter these threats starts with host plant resistance. As well as breeding for resistance, CIP researchers develop and promote integrated pest management (IPM) techniques to increase yields and reduce farmers’ dependence on expensive and harmful pesticides.
Some of Sweetpotato’s Enemies
One of the greatest threats to sweetpotato production is the sweetpotato weevil. The weevil attacks all parts of the plant; adults feed directly on vines, and larvae tunnel into the roots, causing extensive damage both in field and storage. Often causing losses of 60% – 100% during periods of drought, the sweetpotato weevil is a major source of economic loss in developing countries.
Different species prevail in different parts of the world:
- Euscepes postfasciatus occurs in South America and a few other places.
- Cylas fornicarius is present in the Caribbean, southern United States, and Asia.
- The African species Cylas puncticollis and C. brunneus are restricted to sub-Saharan Africa.
- Sweetpotato root knot nematode (Meloidogyne spp) is one of the major known nematode pests of sweetpotato in the tropics. It attacks fibers and roots, allowing other pathogens to penetrate the plant through the wounds.
Whiteflies are widely distributed pests of many agricultural crops and ornamental plants. The species, Bemisia tabaci, is a particularly serious pest of sweetpotato.
Sweetpotato feathery mottle virus and sweetpotato chlorotic stunt virus in combination is known as sweetpotato virus disease (SPVD). Viruses are spread through infected planting material (roots and vines) and are also transmitted from plant to plant by aphids and white flies.
- Integrated Pest Management (IPM)