Screening of plant extracts for organic management of downy mildew of sorghum

Abstract

Antipathogenic potential of 38 plants was evaluated in the form of aqueous extracts against Peronoclerospora sorghi, causing downy mildew of sorghum. Conidial suspension and plant extracts were mixed individually and allowed to stand for 5 min and then used to inoculate the host by sprout-dip method. The sprouts thus inoculated were grown in pots, and the disease incidence was observed. Eight plant extracts (Cicer areatinum, Datura metel, Croton sparsiflorus, Parthenium hysterophorus, Nerium oleander, Chromolaena odorata, Duranta repens and Oxalis latifolia) at 20% concentration performed at par with chemical fungicide (Mancozeb 75%) by exhibiting total suppression of disease incidence to 0%, when compared with 64.1% of negative control. Organic management of air-borne inoculum of downy mildew of sorghum is feasible and preferable when compared with chemical control methods, considering human and environmental health concerns. The use of water extract keeps the technology simple so that it can be directly prepared and used by the farmers. Short-listing of eight most effective water extracts would help in self-reliance of farmers, reducing their dependence on commercial products.