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Three Linnaean names in the genus Rheum are lectotypified: R. compactum, R. palmatum and R. undulatum. [ABSTRACT FROM AUTHOR]

Abstract: Rheum officinale liquid formulation, the ethanol extract from roots of R. officinale Baill., formulated as physcion 5gl−1 aqueous solution (AS), has been commercialized in China for controlling cucumber powdery mildew (Podosphaera xanthii (Castagne) U. Braun & Shishkoff). The efficacy of the product was evaluated in pot tests under controlled conditions and in open and protected fields in China over 2 years. In most trials, the efficacy reached above 80% at the rates of 10–50mga.il−1 water after three applications and at the rates of 20–50mga.il−1 water after two applications. The cucumber fruit yield in the product treatment was as many or more as triadimefon treatment, and over 53.1% compared to the untreated control. These results showed that Chinese rhubarb extract could be an effective alternative plant protecting agent in the integrated and biological management of cucumber powdery mildew. [Copyright &y& Elsevier]