• Worldwide distribution. On sweetpotato. A common, and sometimes serious fungal disease.
• Worse in wet weather.
• Young leaves infected early, especially along veins causing them to distort as they expand.
• Spread is by water splash, wind-driven rain, and on planting material.
• Cultural control: tolerant varieties, which exist in most countries. If susceptible varieties are needed, grow cuttings from sweetpotato storage roots, in a nursery far from production areas.
• Chemical control: mancozeb when symptoms first occur, but likely to be uneconomic.

Sweetpotato scab

Elsinoe batatas, but sometimes known as Sphaceloma batatas (the asexual stage). Usually, only the asexual state is seen on the leaves.