Purple Blotch of Onion
Alternaria porri
Onionfungal
A fungal disease producing purple-brown, concentrically ringed leaf lesions.
Symptoms
Small water-soaked spots that enlarge into purple-brown lesions with concentric rings, leading to leaf collapse in severe cases.
Favorable conditions
- •Warm, humid weather
- •Overhead irrigation and leaf wetness
Management
- 1Rotate fungicides
- 2Rotate crops
- 3Sanitize crop debris
- 4Avoid overhead irrigation
Back to the disease library