Abstract

The effect of three organophosphorus insecticides, viz. fensulfothion, quinalphos and disulfoton on the microflora of a red loamy soil and growth characteristics of ground- nut (POL 1 variety) was assessed in a field trial. The insecticides favoured increases in bacteria. actinomycetes and Azotobacter but not fungi. However, the affect of insecticides on various groups of soil microflora varied with time. Nodulation, shoot and root length and dry weight of plants were not adversely affected by the application of organophos- phorus granular insecticides to the soil. However, yield of pads decreased when soil was treated with quinalphos. But application of fensulfathion and disulfoton increased the pod yield.

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