Evaluation of Fungitoxicity and Structure Activity Relationship of O-aryl O-2-chloroethyl O-ethyl phosphates against Sclerotium rolfsii

Nineteen new O-aryl O-2-chloroethyl O-ethyl phosphate compounds have been found to show fungicidal activity against Sclerotium rolfsii. 4-Nitrophenyl O-2-chloroethyl O-ethyl phosphate analogue (2k) expressed the highest activity with LC₅₀ of 9.12 ppm. 2-Cl; 4-Cl; 2,4-Clj; 2,4,6-CL₃ 2, 4, 5-Cl, and CI, analogues.too, showed better activity than the standard ediphenfos. Quantitative structure activity relationship studies indicated that the fungitoxicity was mainly goverened by the electronic parameters o and F of benzene ring substituents. STERIMOL parameter for minimum and maximum width of the ortho-substituents B1₍₀₎ and B4₍₀₎, also affected the activity.