Impact of different concentrations of quinalphos on growth of aquatic fern Azolla microphylla

The response of the rice field biofertilizer Azolla micraphylla to different concentrations of the insecticide Quinalphos (25 -400 ppm) was premeditated on 6th day after insecticide exposure with respect to growth under taboratory conditions. Insecticide exposure resulted in the reduction of relative growth rate and biomass accumulation at all the concentrations. An increase in the doubling time was also noticed which is an indication of delayed growth. Along with inhibition in growth insecticide application also resulted in reduced total chlorophyll and carotenoid contents ofAzolla microphylla. The preliminary studies on the effect of the insecticide show adverse effect on the growth and physiology of Azalla microphylla which is a non-target organism in the rice fields. Azolla seems to help sustain the soil nitrogen supply by returning nitrogen to quantities roughly equal to those extracted from the soil by the rice plant.