Nematotoxicity of O-Alkyl S, S-Diaryl Phosphorotrithioates against Root Knot Nematode (Meloidogyne incognita) and Relationship between Chemical Structure and Activity*

Twelve new O-alkyl S, S-diaryl phosphorotrithioates assayed for nematicidal activity against the root knot nematode, out of which five evaluated under glass house conditions showed significant reduction in number of galls with maximum reduction in case of O-methyl S, S-di(4-chlorophenyl) phosphorotrithioate. The structure-activity relationships analysed by means of multiple regression analysis using physico-chemical substituent parameters for hydrophobic, electronic and steric properties revealed that the nematicidal activity of the compounds of this series was found to be dependent on lipophilicity of the alkyl groups attached to oxygen and increased with decrease in lipophilicity.