Bacterial spot on pepper caused by Xanthomonas campestris pv. vesicatoria, Race 2, from the south coast of Puerto Rico

Abstract

The incidence and symptomatology of the bacteria! spot on pepper (Capsicum annuum L.) and the identification of the pathogenic race of Xanthomonas campestris pv. vesicatoria (Xcv) (Doidge) Dye involved in the disease complex were studied in commercial and experimental plantations on the south coast of Puerto Rico. Evaluations were made in Juana Díaz, Salinas and Santa Isabel. In commercial plantations cultivar Key Largo showed greater susceptibility than bell pepper. In the experimental plantations, pepper introductions varied in their reaction to Xcv from resistant to susceptible. Xcv isolated from pepper leaves and fruit tissue produced the following symptoms: necrotic lesions with chlorotic halos, raised hyperplastic pustule lesions (open and broken), raised canker-like lesions with chlorotic margins, raised canker lesions with necrotic borders and progressive water soaking. Bacterial strains collected from disease foci in commercial pepper fields were inoculated on the differential lines derived from the susceptible Early Cal Wonder (ECW). On the basis of reactions in the differentials ECW-10R, ECW-20R, and ECW-30R carrying the Bs₁, Bs₂ and Bs₃ resistance genes, respectively, ail the Xcv pepper strains found on the southern coast of Puerto Rico belong to race 2. The absence of other pathogenic races indicates that Xcv race 2 produces diverse symptomatology in peppers in Puerto Rico.