Many xenobiotic compounds have long-term stability in soil, and their persistence results in significant impact on the soil ecosystem. A laboratory study was done to determine the impact of two selected insecticides, Oxydemeton Methyl (Organophosphorus), Emamectin Benzoate (Evermectin) and two selected fungicides Dithane-Z-78 (Dithiocarbamate), Benlate (Benzimidazole) on phosphatase enzyme activity in two different soil samples (Black clay soil and Red sandy loam soil) of Groundnut (Arachis Hypogaea L.) cultivated fields in Anantapuramu district of Andhra Pradesh, India. The soil samples were treated with insecticides and fungicides at five different concentrations i.e., 10, 25, 50, 75,100 ppm, which are equivalent to field application rates (1.0, 2.5, 5.0, 7.5, 10.0 kg ha-1 ). We observed that phosphatase enzyme activity significantly enhanced at 2.5 kg ha-1 in both the soil samples after 10 days of incubation. After the prolonged incubation upto 30 and 40 days, there was a decline in phosphatase enzyme activity, However stimulation was observed with four pesticides incubated for 20 days at 2.0 kgha–1 .
