Quantitative Structure Activity Relationship Study for the Fungicidal and Nematicidal Activity of Phenols

Twenty eight differently substituted phenols were evaluated in vitro for fungicidal activity against Rhizoctonia solani and Sclerotium rolfsii and for nematicidal activity against Meloidogyne incognita and Rotylenchulus reniformis. Among all, 2,4,5-trichlorophenol showed highest fungicidal activity and 3,4-dimethylphenol highest nematicidal activity. The quantitative structure activity relationship (QSAR) models revealed that the fungicidal activity of phenols against R. solani was dependent upon the electronic nature and bulkiness whereas against S. rolfsii on hydrophobicity and the shape and size of phenol substituent. The hydrophobicity of the phenol substituents was found to be important for imparting nematicidal activity against both the test nematodes and showed parabolic relationship.