General Information: This plant pathogen affects rice plants by causing leaf blight, a major problem in Asian countries where rice production occurs on an industrial scale. Causes disease in rice. These organisms are almost exclusively found associated with their plant hosts and are not found free in the soil. Xanthomonas oryzae contains two pathovars which cause enconomically significant diseases in rice. Xanthomonas oryzae pathovar oryzae causes bacterial leaf blight which is one of the most serious diseases of rice. This disease is common in temperate and tropical areas and can cause significant crop loss.