Efficacy of Reynoutria sachalinensis for control of bacterial leaf spot and powdery mildew on tomato in Florida

Jason Osborne, Timothy Johnson, David Warman, Hai Su, Marja E. Koivunen, Pam G. Marrone


The extract of Reynoutria sachalinensis F. Schmidt (formulated as Regalia®), controls powdery mildew and other diseases on many crops by induction of plant systemic resistance and by inhibition of conidia germination. A field study was conducted near Hobe Sound, FL, by Glades Crop Care on tomato (Lycopersicon esculentum Mill.) to test the efficacy of the extract of Reynoutria sachalinensis against tomato bacterial leaf spot [Xanthomonas campestris pv. vesicatoria (Doidge) Dye] and powdery mildew (Oidium neolycopersici L. Kiss sp. nov.). Formulated Reynoutria sachalinensis extract was tested as a stand-alone treatment as well as in a tank mix or in rotation with maneb, copper or chlorothalonil. All Reynoutria sachalinensis treatments resulted in a signifi cant reduction in the severity of bacterial leaf spot, and the efficacy was not significantly different to that obtained with maneb (Maneb® 75DF) and copper (Kocide ® 2000) rotated with chlorothalonil (Bravo Weather Stick®). For powdery mildew control, Reynoutria sachalinensis as a stand-alone treatment significantly reduced disease incidence and performed better at 1.0% than at 0.5% (v/v, formulated product) concentration. There were no significant differences between tank-mix and rotation treatments in the control of both diseases.

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283