Bacterial blight (angular leaf spot) of cotton

Symptoms

Small, water-soaked angular spots on leaves, bounded by the veins, later turning brown; black, greasy lesions run along stems ('black arm'); sunken dark spots rot the bolls and stain the lint. Spread by rain-splash and worst in warm, wet, windy weather.

Plants affected

• cotton (upland cotton)

Common questions

How do I recognise Bacterial blight (angular leaf spot) of cotton on cotton (upland cotton)?

Small, water-soaked angular spots on leaves, bounded by the veins, later turning brown; black, greasy lesions run along stems ('black arm'); sunken dark spots rot the bolls and stain the lint. Spread by rain-splash and worst in warm, wet, windy weather.

Do I have to report Bacterial blight (angular leaf spot) of cotton?

No. Bacterial blight (angular leaf spot) of cotton is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is Bacterial blight (angular leaf spot) of cotton treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.