Evaluation of integrated management of bacterial wilt of tomato using grafting, biofumigant and plant resistance activator under field conditions

Abstract

Bacterial wilt, caused by Ralstonia solanacearum, is a major and constant constraint in the production of tomatoes worldwide. A two-season field experiments, laid out in two separate orchards in a randomized complete block design and a split-split plot arrangement with three replications, was conducted to evaluate the integrated effect of grafting, thymol and acibenzolar-S-methyl (ASM) in the management of tomato bacterial wilt disease in a naturally infested soil. Beske and UC82-B tomato cultivars, susceptible to the pathogen, were grafted on a resistant tomato rootstock (Tomachiva) while thymol (0.7% w/v) was applied as a pre-plant soil fumigant. Grafted and non-grafted tomato received ASM as foliar spray after transplanting. Sole or combined application of the enhancers (thymol and ASM) had significant reduction of bacterial wilt incidence in both seasons, from the second to eight weeks after transplanting. At eighth week after transplanting, the effect of combined application of thymol and ASM translated to 100% and 90.3% disease reduction in early and late planting seasons, respectively. Grafted tomato, thymol and ASM combination produced an average yield of 74.3 and 86.9 ton/ha in early and 65.3 and 58.1 ton/ha in late planting seasons respectively. The findings indicated that integrated use of grafting, thymol (0.7% w/v) and ASM (30 µg/ml) could be of great benefit in the control of bacterial wilt of tomato.