Acybenzolar-S-Methyl, Inducer of Resistance against an Abiotic Stress (Blossom End Rot) on Industry Tomato

Acybenzolar-S-Methyl (ASM) is a synthetic inducer and a functional analogue of salicylic acid, involved in the mechanism of the systemic acquired resistance (SAR). Different studies performed under controlled environmental parameters have shown that the molecule plays a key role in the control of water stress in tomato. In fact, tomato plants treated with ASM were more resistant to water stress for a longer period than untreated ones. This behavior was associated with the expression of a pattern of proteins, involved in defense mechanisms/stress responses, in photosynthetic metabolism and into the energy metabolism, whose production was specifically induced by treatment of plants with ASM. In order to verify if ASM is involved in the control of water stress (and in particular blossom end rot, BER) in natural conditions as well, a field trial was carried out during 2013 crop season at the “Centro per la Sperimentazione e Valorizzazione delle Colture Mediterranee” – Syngenta, in Foggia (southern Italy). The experiment was arranged in a split-plot with a plant density of 2.8 plants m-2. ASM was applied alone or combined with azoxystrobin on tomato plants, starting from the flowering stage, in three different application timings, at dose of 0.025 kg ha-1. The experiment included applying three different water regimes through a drip irrigation system. At harvest, the number of fruit with signs of BER were evaluated on six plants per replicate, selected randomly. Under 75% of the optimal irrigation volume regime ASM has shown the higher marketable yield and the best control activity on tomato fruits.