Seasonal Variations in Incidence and Severity of Bacterial Spot and Bacterial Speck of Tomato (Solanum lycopersicum L.) Under Rain-Fed and Irrigated Conditions In Samaru Zaria, Nigeria

Abstract

Tomato production is hampered by many constraints, including insect pests and diseases. Among the important diseases are bacterial spot and bacterial speck, caused by Xanthomonas vesicatoria and Pseudomonas syringae pv. tomato, respectively. These diseases have been reported to cause remarkable yield loss in all tomato producing areas. This study was therefore under taken to evaluate the reaction of some tomato varieties to bacterial spot and bacterial speck diseases under screenhouse and field conditions and determine the seasonal variation in the incidence and severity of the disease on the field under natural infection. Screenhouse experiments were carried out in a completely randomized design while field experiments were done using randomized complete block design. Four tomato varieties (RomaVF, UC - 82, Tima and Rio Grande) were evaluated, and Koch‟ spostulate was confirmed to ascertain infection by the pathogens. The results indicated that all seed samples obtained from farmer saved stocks were infected with bacterial spot while those from the open markets/certified seed vendors were not infected with the pathogen. Among the varieties evaluated for resistance, none was resistant to the pathogens with Rio Grande being the most tolerant. On the field, incidence (35.0%) and severity (1.6+0.17) of bacterial spot was more severe in the wet season than in the dry season in 2010/2011 also incidence (33.0%) and severity (1.7+0.23) of bacterial spot was more severe in the wet season than in the dry season of 2011/2012 while bacterial speck was also not detected in both seasons.