The impact of two selected insecticides i.e. phenthoate (Ethyl (dimethoxyphosphorothioyl) sulfanyl (phenyl) acetate) and λ-cyhalothrin (alpha-cyano-3-phenoxybenzyl-3-(2-chloro3,3,3-trifluoroprop-1- enyl)-2,2-dimethyl-cyclopropane-carboxylate) on selected soil enzymes phosphatase and urease were determined in two different soil samples ( red sandy loam and black clay soils) of groundnut (Arachis hypogaea L.) cultivated fields in Anantapuramu district of Andhra Pradesh, India. A laboratory experiment was conducted to determine the effect of selected insecticides, Phenthoate (organo thio phosphorus) and λ-cyhalothrin (pyrethroid) at different concentrations ranging from 1.0 to 10 kg ha-1. The soil samples receiving 5.0 kg ha-1 of selected insecticides were significantly more in both soil samples after 10 days of incubation. The activity of the phosphatase and urease was decreased progressively with the increasing period of incubation up to 30 and 40 days. Similarities were found between the results obtained with the selected enzymes in the soils but comparatively the stimulatory effect was more by phenthoate than λ-cyhalothrin.
