A statewide survey of commercial irrigated pepper fields was conducted in Katsina, Nigeria to gain information on the incidence of diseases with wilt symptoms, their causative organisms, and the existing pepper production systems. Eighty fields were surveyed at different growth stages of pepper plants. Diseased plants with wilt symptoms occurred in all fields. The percentage wilt incidence in each field ranged from 50 to 100%. Field diagnosis, along with laboratory assays of wilted plants, revealed that the wilting was caused by Ralstonia solanacearum and Phytophthora capsici. The two pathogens were found in 88% of the fields and occurred together in 12% of the fields. Interviews conducted to assess farmers' practices, which contribute to pathogen damage, showed that successive planting of susceptible crops without land rotation may have contributed to the build up of the soil populations of the pathogens. The mode of irrigation also contributed to the pathogen control failures. Intercropping pepper with crops such as tomato ( Lycopersicum esculentum) and Solanum species did not reduce disease incidence in some areas. Results indicate the necessity for the adoption of integrated pest management strategies in pepper production in Katsina State, Nigeria.
