Effect of some plant extracts on Rhizoctonia spp. and Sclerotium hydrophilum

Soilborne phytopathogens affect rice production by inhabiting inoculum permanently in the soil. Pesticides of plant origin are preferred in order to reduce the risks involved in chemical control measure. The present study was conducted to find out bioresource to control some rice pathogens. Sixteen naturally available phytoextracts were tested in vitro for their potential to control phytopathogens of rice, such as Rhizoctonia solani, Rhizoctonia oryzae,Rhizoctonia oryzae-sativae and Sclerotium hydrophilum. All of the tested fungal growths were suppressed 100% by using clove extract. Neem leaf, rosemary and pelargonium extracts were found to give the second best suppression against the tested fungi. Neem leaf extract inhibited the growth of R. solani by 87.5%, R. oryzae by 92.5% and R. oryzae-sativae by 80%. However, the same extract inhibited S. hydrophilum by only 49.1%. Rosemary extract gave an inhibition of 67.7% for R. solani, 88.0% for R. oryzae, 86.0% forR. oryzae-sativae and 73.89% for S. hydrophilum. The inhibitory effect of pelargonium on the tested fungi showed 48.1% for R. solani, 90.8% for R. oryzae, 84.4% for R. oryzae-sativae and 83.3% for S. hydrophilum. Among the tested phytoextracts, cloves, neem leaf, rosemary and pelargonium are potential phytoextracts to control the tested soilborne phytopathogens.   Key words: Rice, Rhizoctonia solani, Rhizoctonia oryzae, Rhizoctonia oryzae-sativae,Sclerotium hydrophilum, sheath diseases, phytoextract.