RESISTANCE TO TOMATO BACTERIAL WILT INDUCED BY ACIBENZOLAR-S-METHYL

The present study was undertaken to evaluate the potential of acibenzolar-S-methyl as a plant resistance activator against tomato bacterial wilt caused by Ralstonia solanacearum. Plants of the cultivars Santa Clara, Diana and AF-2573 received seven weekly applications of acibenzolar-S-methyl (ASM, 2.5 g a.i./100 L water), by foliar sprays or soil drenches. The first application was carried out 14 days after sowing. Thirty-two day-old plants were transplanted into soil infested with R. solanacearum and four weekly applications of the activator were made after transplanting. Plants in control plots received plain water. Disease incidence was evaluated daily as the number of wilted leaves and plants. Data obtained allowed the estimation of the area under the disease progress curve (AUDPC). Wilt symptoms increased at a slower rate in the three cultivars when ASM was sprayed onto plants. This effect was significant up to four weeks after transplanting to R. solanacearum-infested soil.