Bacterial Blight in Cotton

Cotton is a crop that is susceptible to a multitude of different economically impactful diseases, and as with other agronomic practices, disease protection and prevention can drastically impact yields and the grower’s bottom line. Bacterial blight, also known as angular leaf spot, is a foliar disease caused by the pathogen Xanthomonas citri pv. Malvacearum. The symptoms of bacterial blight can be observed on all above-ground parts of the plant, including leaves, petioles, and fruit.

As with most foliar diseases of cotton, bacterial blight is most commonly associated with extended periods of rainfall and general wetness of the crop. Rainfall, high humidity, cloudy weather, and lack of breeze to dry the foliage by mid-morning all increase the probability of infection. Foliar symptoms can appear as “angular” lesions or spots on the leaves and often have a wet or water-soaked appearance as well as darkened water-soaked streaks down the leaf veins (Picture 1).

Picture 1:

📸: BASF employee/Featuring bacterial Blight susceptible variety (Left); bacterial Blight resistant Axant™ Flex seed technology in experimental variety (Right).

Infected leaves will often prematurely defoliate from the plant, decreasing the plant’s photosynthetic capability. Lesions may also appear on the bolls as round, sunken, water-soaked spots on the bolls (Picture 2). These lesions may inhibit the boll’s ability to open as well as cause boll rot, either from the pathogen itself or through secondary infection from other pathogens.

Picture 2:

📸: BASF employee/Featuring bacterial Blight susceptible variety (Left); bacterial Blight resistant Axant™ Flex seed technology in experimental variety (Right).

Unlike fungal diseases, bacterial blight cannot be prevented or controlled through the use of fungicides. The selection of resistant varieties is the only viable control for bacterial blight in cotton. There are many resistant variety options in the Fibermax® seed technology and Stoneville® seed technology portfolios, including varieties in our new Axant™ Flex technology lineup.

Contact Your BASF Representative 

Every crop year brings new challenges, and our battle with bacterial Blight can be one of farming's biggest sources of frustration. If you’ve encountered disease-related damage to your cotton and would like to discuss expert recommendations on resistant varieties in your area, reach out to your BASF representative. We’re here to help.

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