Coffee Leaf Rust
Hemileia vastatrix
Overview
The most economically important disease of coffee worldwide, causing orange-yellow powdery lesions on leaf undersides. Has devastated coffee production in multiple regions over the past 150 years.
Symptoms
Orange-yellow, powdery pustules on leaf undersides. Corresponding yellow spots on upper leaf surface. Premature defoliation. Reduced berry production. Dieback of branches in severe cases. Multi-year yield decline.
Environmental Conditions
Humid
Prevention
Plant resistant varieties (Catimor, Colombia, Castillo). Shade management. Proper nutrition (especially potassium). Fungicide applications during rainy season. Good air circulation.
Management
Apply copper-based or triazole fungicides. Prune to improve air circulation. Maintain adequate nutrition. Stumping severely affected trees for regrowth. Replant with resistant varieties.