Preliminary results on the effect of Acibenzolar-S-Methyl on abiotic stresses in tomato: "Blossom end rot" control

Blossom-end rot (BER) is caused by a localized Ca deficiency in the developing tomato fruits. It begins with light tan, water-soaked areas that can then enlarge and turn black and leathery in appearance. Most often the problem occurs at the blossom end of the fruit, but on occasion it can occur on the side of the fruit. Since it has been hypotesised that the SAR inducer Acibenzolar-S-Methyl (ASM) increases the resistance of plants against abiotic stresses such as drought, cold, heat and salinity, a study was performed in 2012 with the purpose of evaluating its effect in the induction of resistance to this disorder in tomato grown under tunnel. ASM 2.5 g/hl was applied in five different application timings, every ten days, starting from the day prior to transplantation. Three different assessments of eventual phytotoxic effects on the vegetative part of the plant and of the degree of BER on each fruit cluster were carried out respectively 7 days after the 4th application and 10 and 30 days after the last one. No phytotoxicity was observed. Our preliminary results clearly demonstrate that tomato grown under tunnel, treated with ASM, shows a substantial reduction of sensitivity to BER. In particular, a statistically significant difference in BER with the untreated control was present on the 1st fruit cluster, decreasing toward the 2nd, and not detectable on the 3rd and 4th ones, may be because of the strong reduction of the disorder at this stage, and most probably also because of the reduction of the effect of ASM in plants about one month after the last application. In the light of the results obtained, studies are in progress aiming at verifying the effect of application timing of ASM on the control of physiological disorders from water stress, the dose effect of ASM application, the effect of different environmental conditions with particular reference to the temperature, and the efficacy of treatment with ASM for the control of water stress in tomato in combination with chemicals capable of mobilizing or supplying Ca to tomato plants.