Pacific Pests, Pathogens and Weeds

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Summary

• 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.