Influence of Insecticides Thiodicarb and Dimethoate on Soil Microbial Activities (Phosphatase) in two Groundnut

In Agricultural practices pesticides are used for crop production and to produce high yield. But indiscriminate and excessive use of pesticides in agriculture leads to environmental pollution and in soil it is not degrading. A pesticide disturbs the activities of soil enzymes and soil micro biota. So we investigated in laboratory conditions that the effect of two insecticides, Thiodicarb (Dimethyl N, N '(thiobis ((methylimino) carbonyloxy)) bis (ethanimidothioate) and Dimethoate (O, O-dimethyl S-[2-(methylamino)-2-oxoethyl]) dithiophosphate) on enzyme activity, such as Phosphatase in two soils collected from groundnut (Arachis hypogaea. L) cultivated fields of Anantapuram district of Andhra Pradesh, India, by conducting experiments at different concentrations (10, 25, 50, 75, 100ppm) which are equivalent to field application rates (1.0, 2.5, 5.0, 7.5,10.0 kg ha). In our present study we observed, Phosphatase activity were significantly enhanced at 2.5 and 5.0 kg ha in black and red soils after 10 days of incubation. Furthermore increase in concentration of insectcides and decreased the rate of enzyme activity. However the stimulatory effect was continued up to 20 days of incubation in black and red soils. Whereas, the decline phase was started after 20 days and the minimum enzyme activities were noticed at the end of 40 days of incubation. But higher concentrations of insecticides at the level of 7.5 to 10.0 kg ha were either toxic or innocuous to phosphatase activity in black and red soils. © 2017 Universal Research Publications. All rights reserved