Influence of selected insecticides on phosphatase activity in two Groundnut (Arachis hypogaea L.) soils

Organophosphorus, neonicotinoid insecticides are widely used in India for protection of agricultural yields from more than 120 pests. However, these pesticides pose various threats to organisms, including humans, and hamper soil microbial activity; thus, they are a cause for serious concern. Among them, peanut stem necrosis disease and sucking pests are the major threats to the groundnut (Arachis hypogaea L.) crop in Anantapur district of Andhra Pradesh. In the present study, we used imidacloprid, which is a neonicotinoid and acephate an organophosphorus insecticide against these diseases to check the soil health and fertility by knowing the activities of enzymes epecially phosphatase, under laboratory conditions in two groundnut (Arachis  hypogaea L.) soils.  The activity of phosphatase was more pronounced at 5.0 kg ha-1 in black and red sandy clay soils after incubation for 10 days. The enzyme activity was further enhanced up to 20 days of incubation, whereas, decreased the activity at 30 and 40 days of incubation. However higher concentrations of 7.5kg ha-1 and 10.0 kg ha-1 were toxic to phosphatase activity in both soils.