Abstract
Foliar sprays of validamycin A (VMA) controlled cabbage black rot effectively in pot and field trials. In a pot test, VMA reduced the number of Xanthomonas campestris pv. campestris (Xcc) in leaves. VMA inhibited the production of extracellular polysaccharide (EPS) on yeast-peptone (YP) agar containing carbohydrates. Injection of EPS from Xcc on medium containing VMA produced fewer lesions than that without VMA. These results suggested that VMA might inhibit the multiplication of Xcc in plants and affect the quantity and quality of EPS. © Pesticide Science Society of Japan