Pseudomonas fluorescens based bio-formulation for the management of sheath blight disease and leaffolder insect in rice

The talc-based formulation of two Pseudomonas fluorescens strains (PF1 and FP7) and its mixture (with and without chitin) were tested against sheath blight and leaffolder in rice. The application of talc-formulation through seed, root, soil and foliar spray significantly reduced the sheath blight and leaffolder incidence both under greenhouse and field conditions. The mixture of two strains performed better than the individual strains. In field trials the maximum of 62.1% sheath blight and 47.7-56.1% reduction in leaffolder incidence was noticed in the mixture treatment containing chitin and its efficacy was equivalent to standard fungicide and insecticide treatments. Pseudomonas treated leaves altered the feeding behaviour of leaffolder larvae and reduced larval and pupal weight, increased larval mortality and incidence of malformed adults under in vitro. An increased population of natural enemies of leaffolder viz., hymenopterous parasitoids and predatory spider was noticed in Pseudomonas treated plots under field conditions, which, yielded 12-21% more rice. (C) 2002 Elsevier Science Ltd. All rights reserved.