Symptoms
Angular water-soaked spots between leaf veins that turn brown, with gummy ooze on the underside and along the stem. Severe attacks cause wilting, dieback of shoots and blackening of the vascular tissue.
Prevention
Plant clean, certified cuttings and resistant varieties; never take cuttings from infected fields. Rotate crops, disinfect tools, and avoid working among plants when wet.
Treatment
Organic
Remove and burn infected plants and use copper-based bactericide as a protectant. Improve spacing and drainage to reduce humidity around the canopy.
Chemical (last resort)
Apply copper oxychloride sprays preventively during wet weather; there is no curative chemical. Combine with strict sanitation and observe PHI.
Affects 1 crop
Sources
MARDI Cassava Production Guide; DOA IPM Manual