MBI-R20, a new pesticide, induces resistance in plants and controlsboth fungal and bacterial plant diseases

Abstract: A biofungicide formulated from Reynoutria sachalinensis extract, MBI-R20, controlspowdery mildew and other diseases on many crops by induction of the production of plantphytoalexins and simple phenolics, and by inhibition of conidia germination. Field studiesconducted in multiple locations on specialty crops such as cucurbits, tomato, lettuce, and winegrapes indicate good efficacy against major fungal and bacterial plant pathogens. In a field studyon tomato, MBI-R20 applied either alone or in a tank mix with common chemical fungicidesresulted in a significant reduction in severity of bacterial spot (Xanthomonas campestris pv.vesicatoria) and reduced incidence of powdery mildew (Oidium neolycopersici). The efficacywas equal to that obtained with the growers’ standard chemical pesticide treatments included inthe study. For powdery mildew control, MBI-R20 as a stand-alone treatment (8 applicationsevery 5-7 days) performed better at 1.0 than 0.5% concentration in this study, but both ratescontrolled bacterial leaf spot equally well. There were no significant differences among the MBIR20stand-alone, tank-mix and rotation treatments in the control of both test pathogens, whichindicates that MBI-R20 can be successfully included in integrated pest management programs todecrease the risk of resistance development among plant pathogens. Preliminary results fromrecent field studies on wheat suggest that besides pesticidal effect against Septoria sp., MBI-R20also has a beneficial effect on yield quality in terms of higher protein content and grain weight.