Pacific Pests, Pathogens & Weeds - Mini Fact Sheet Edition

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Sweetpotato scab (013)

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Photo 1. Distorted, torn leaves showing the brown scabby areas along the veins and leaf stalks caused by Elsinoe batatas. These are the places where the spores are produced.

Photo 2. Twisted, deformed leaves showing the undersurfaces and the brown scabby areas of Elsinoe batatas. Many of the scabs are on the leaf veins and petioles.

Photo 3. Twisted leaves of sweetpotato exposing the undersides, due to infection by the scab fungus, Elsinoe batatas.

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.

Common Name

Sweetpotato scab

Scientific Name

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

This mini fact sheet is a part of the app Pacific Pests, Pathogens & Weeds

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