Twenty-eight new oxa (thia) diazolyl 3 (2 H)-pyridazinone derivatives were synthesized. Some compounds showed good chronic growth activities against the armyworm, Pseudaletia separata (Walker). Their EC50 values were determined in vivo. Nineteen 2-tert- butyl-4-chloro-5-[5'-aryl-2'-(1', 3', 4'-oxadiazolyl) methoxy]-3 (2 H)-pyridazinones were quantitatively analyzed using the QSAR procedure. The partial least squares method was ...
