Effect of Acibenzolar-S-Methyl on severity of Fusarium wilt and fruit yield of two tomato cultivars

Tomato wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) is one of the limiting factors to tomato production in the whole world  because of its negative effect on the fruit yield of tomato. The study investigated the application of Acibenzolar-S-Methyl (ASM), a plant  activator that stimulates plants’ defence mechanisms, at different concentrations (0, 25, 35 and 45 mg/L) on two tomato genotypes  (Delila and Kerewa) using drenching method. Factorial experiments were laid out in a randomized complete block design and completely  randomized design in both field and the screenhouse, respectively. Results showed that the application of ASM significantly reduced  (p≤0.05) disease severity. At 9 weeks after transplanting Delila recorded severity scores of 3.00 and 3.33(screenhouse) and 0.33 (field)  while Kerewa had severity scores of 1.33 and 1.50 (screenhouse) and 0.33 (field) when ASM was apllied at 35 and 45 mg/L concentrations,  respectively. These values were significantly lower (p≤0.05) than those recorded in untreated plots. Delila yielded 151.23 and 151.73 kg/ha  (screenhouse), and 754.70 and 795.8 kg/ha (field) while Kerewa yielded 109.60 and 124.03 kg/ha (screenhouse) and 601.10 and  279.8 kg/ha (field) when ASM was apllied at 35 and 45 mg/l concentrations, respectively. Yields in both screenhouse and the field were significantly higher (p≤0.05) than yields in the untreated control plots. The study concluded that application of ASM at 35 and 45 mg/L to  tomato could enhance its resistance which would translate to fruit yield increase.