Effect of Raw Cow Milk and Gliocladium virens in Pearl Millet against Downy Mildew Disease Caused by Sclerospora graminicola

Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] downy mildew (DM) is caused by the fungus Sclerospora graminicola (SACC.) SCHRŐT. is the most widespread and destructive disease of pearl millet affecting yield and quality in all the millet cultivating tracts of India. Since pearl millet is a crop of low economic value grown by resource-poor farmers, conventional technological interventions are not cost feasible. Integration of indigenous knowledge with biocontrol agents appeared as a logical strategy in the present case. Studies were, therefore, undertaken to manage DM in rainfed crop of pearl millet using raw cow milk together with Gliocladium virens. Seed and soil treatments resulted in the lowest disease incidence. Biochemical constituents (metabolites and oxidative enzymes) were analysed to determine possible mode of action of Raw Cow Milk (RCM) and Gliocladium virens. A considerable increase in sugars, phenols and ortho-dihydroxy phenols (OD) in healthy and DM infected leaves of treated pearl millet plants was recorded when compared to untreated controls. A marked increase in all the photosynthetic pigments in both healthy and diseased treated plants was observed. The induction of resistance was accompanied by increased activities of defense related enzymes. It is assumed that the combination of RCM and G. virens is capable of stimulating different systemic responses in host plant.