SEVERITY OF SOME FOLIAR DISEASES ON SELECTED TOMATO VARIETIES AND ASSOCIATED PATHOGENS IN A DERIVED SAVANNAH AGROECOLOGY

Tomato leaf diseases can be severe, causing defoliation and eventually killing the plant if not properly managed. Estimating disease severity is crucial for disease management and yield loss prediction. Detection and identification of pathogens enable selection of pathogen-free planting materials that are essential for improved yield and quality. The present study identified the pathogens associated with foliar diseases of four tomato varieties, assessed the incidence and severity of these diseases and determined the effect of these foliar diseases on some growth parameters. Four tomato varieties (Tropimech, Tima, Roma VF and Omu-Aran local) were raised in the nursery and transplanted to Sites A and B on the field. The experimental design was a randomized complete block design with three replicates. Leaves of the tomato plants were observed for foliar disease symptoms. The pathogens associated with the diseases were identified. Data were collected on observed incidence and severity of foliar diseases, plant height, number of leaves and branches at 2, 4 and 6 weeks after transplanting (WAT). Data collected were subjected to analysis of variance using statistical package for social sciences (SPSS) package and means were separated using Duncan multiple range test at 5% probability level. The identified foliar diseases were early blight (Alternaria solani), bacterial wilt (Ralstonia solanacearum) and curly top (curly top virus). Roma Vf had the highest incidence of early blight (83.4%) at 6 WAT in Site A. At 4 WAT in Site A, Tima had the highest severity of bacterial wilt (3.5), followed by Tropimech (2.5). AT 6 WAT in Site B, the tallest plants was recorded on Roma Vf (28.5cm), followed by Omu-Aran local (27.3cm) and Tropimech (19.5cm) and the lowest number of leaves was recorded on Tima (9.8) in Site A. At 6 WAT in Site B, Roma Vf had the highest number of branches (13.5). Bacterial wilt was the most severe foliar disease encountered in the study area. Roma VF and Omu-Aran local are recommended for planting in areas where bacterial wilt is widespread while Tima is suitable where early blight is prevalent. Findings from this study can serve as bedrock for breeding and selection of foliar disease resistant tomato varieties. Keywords: Tomato, foliar diseases, pathogens, disease incidence, disease severity, growth parameters