- Widespread distribution. Asia, Africa, Oceania. On sweetpotato and relatives. Occasionally, an important disease.
- Veins on young leaves show clearly, side shoots grow, becoming bushy, erect, with small leaves.
- Caused by bacteria-like organism in phloem tubes.
- Spread by leafhoppers that feed on diseased plants then infect others after 20 days. More important in dry times. Storage root yields absent or very low.
- Cultural control: plant only disease-free vines; do not plant near infected crops; remove affected plants when seen; collect and burn trash after harvest.
- Chemical control: PDPs: derris, pyrethrum, or chilli; or synthetic pyrethroids.
