Sweet Potato Weevil
The adult form of the sweet potato weevil is a shiny black antlike insect with a long snout and a red “neck” (technically speaking, a prothorax). It feeds on sweet potato foliage but usually does little damage. It’s the pest’s white larvae that tunnel into sweet potato tubers, causing damage that frequently leads to root rot.
The sweet potato weevil overwinters in stored sweet potatoes or on nearby weeds such as wild morning glory. Eggs are laid in cavities of the sweet potato root or on the vine near the soil surface. As many as eight generations can occur in a single year. Sweet potato weevils are found in the southern United States from Louisiana to Texas and north to North Carolina.Prevention and Control
- When purchasing sweet potato slips or seed potatoes, make sure they are certified weevil-free.
- Rotate crops to avoid planting sweet potatoes in the same bed more than once every three years.
- Mound soil around the base of the plant to help protect the stems from egg-laying adults.
- Mulch the soil to help keep it moist and prevent cracking, which gives adults easier access to sweet potato roots.
- Remove any wild morning glory vines growing nearby. Clean up all weeds and leftover sweet potatoes at the end of the season.