Abstract
SAR inducers and dioxygenase-inhibitors represent an alternative approach for controlling fire blight. Acibenzolar-S-methyl (AMB), prohexadione-Ca (ProCa) and trinexapac-ethyl (TrixE) were tested in vitro and field conditions for their efficacy in reducing fire blight incidence and severity. A reduction of up to 50% of blossom blight was observed. In addition, treatment with one of these compounds significantly reduced the percentage of flower infections that successively developed into shoot blight. Similarly, in vitro, resistance inducers slowed down the pathogen migration both in the xylem and in the parenchyma. In particular, the application of ProCa and TrixE resulted in a 50-60% inhibition of pathogen migration inside the plant tissues [1]. The acylcyclohexanediones have also been combined with a biological control agent: Pantoea agglomerans (EhC9-1 and P10c). Treatments with such a combination resulted in 75% less flower infected developing into shoot blight than when treated with water. This level of reduction was higher than that observed for either EhC9-1 or an acylcyclohexanedione by itself. This synergic effect could be the result of combining complementary modes of action