Bacterial blight
A bacterial disease that causes water-soaked angular leaf spots and dark spots on pods and fruit in beans, pomegranate, geranium and other plants.
Also known as: Halo blight, Common blight
Symptoms and identification
Small, water-soaked spots turn brown, often with a yellow halo or an angular shape between the veins. On pomegranates, dark spots appear on leaves and fruit and cracks may form. On beans, pods show sunken, greasy spots and plants may be stunted.
Causes
The bacteria survive on seed, plant debris and in soil, and spread by splashing rain, wind, tools and handling wet plants. Warm, humid, wet weather and wounds from hail or insects make infection more likely.
Organic treatment
Remove and bin infected leaves, pods and fruit. Copper-based sprays used early may slow spread but do not cure existing infection.
Prevention
Use certified disease-free seed and plants, avoid handling plants when wet, water at the base and rotate crops. Clear debris and sterilise tools. Prune pomegranates for airflow.
Chemical treatment (use with care)
A copper bactericide labelled for the crop, applied at first symptoms and repeated as the label says, is the usual chemical option.