Evaluation of plant extracts against Rhizoctonia solani causing sheath blight of rice
Anil Sehajpal, Saroj Arora and Parminder Kaur
The antifungal effect of 44 plant extracts and 8 plant oils against the pathogen Rhizoctonia solani was evaluated by disc diffusion method. Out of 44 plants tested, 36 plant extracts showed varied degree of antimicrobial effect at different concentrations against the pathogen whereas 8 plant extracts, viz. Abrus precatorious, Acacia auriculiformis, Bougainvillea glabra, Convolvulus arvensis, Hibiscus rosa-sinensis, Morus alba, Thevatia peruviana, and Withania somnifera did not exert any effect. Among all the plant extracts, A. sativum exhibited strong fungitoxicity even at the lowest concentration, i.e. 100 ppm, with relative magnitude of inhibition 2.0 mm against the pathogen R. Solani. With regard to the effect of 8 plant oil samples tested, it was noticed that the oil of Syzygium aromaticum showed strong inhibition i.e. 7.5 mm at 1000ppm whereas Helianthus annus and Oryza sativa were ineffective.