What caused the irregular necrotic spots on this mustard?
These irregular spots are a symptom of bacterial leaf blight (Pseudomonas cannabina pv. alisalensis). This bacterial disease of brassicas is most serious on mustard and turnip. Bacterial leaf blight typically appears in the fall or spring and can spread to healthy plants through splashing rain. This is a particularly difficult disease to manage as bactericides are ineffective, and there are few resistant cultivars available.
Since bacterial leaf blight first appeared in South Carolina around 15 years ago, USDA and Clemson researchers in Charleston have been focused on breeding resistant mustard cultivars. One such variety released in 2015 is ‘Carolina Broadleaf,’ a flat-leaf mustard. A slower-bolting flat-leaf cultivar, ‘Charleston Broadleaf,’ was introduced last year. These researchers are also working on curly-leaf cultivars. Read more about their efforts in this recent Clemson World article.
This week’s question is from Justin Ballew, Extension Fruit and Vegetable Research Associate.
