Assay of some systemic insecticides againstHyadaphis erysimi (Kalt.) onBrassica campestris L., var,sarson Prain

Five systemic organophosphorus insecticides were tested for their intrinsic toxicity in laboratory and persistence of their field-weathered deposits following spray onsarson crop (Brassica campestris L., var.sarson Prain) at recommended concentrations against mustard aphidHyadaphis erysimi (Kalt.). Phosphamidon and demeton-S-methyl proved to be sufficiently toxic compounds and provided protection to the crop for more than 3 days. Thiometon compared to dimethoate was a less toxic insecticide but relatively more persistent. Formothion was found to be the least toxic and least persistent insecticide.