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Volume: 3, Issue: 5, Sep-Oct, 2015
Effect of cypermethrin, a pyrethroid insecticide on dynamics of soil microflora
Bijay Kumar Sethi, Subhashree Pradhan, Narayan Behera, Santi Lata Sahoo
Soil samples were collected from garden of P.G. Department of Botany, Utkal University, Odisha India. The physical analysis of soil revealed that texture of the soil was sandy loam with pH 5.7, temperature 34.6ºC, 5.7% water content and 67.3% water holding capacity, respectively. Utmost numbers of Aspergillus species with other fungi were isolated from garden soil (5×105 CFU/g). Total 19 fungal taxa were isolated from all the samples studied. The isolated species were belonging to 8 genera representing the genus Aspergillus as dominant one. Total twelve fungal species of six genera were recorded from air of the pesticide treated soil area. Soil treated with 600ppm cypermethrin exhibited ten fungal species. Out of which, A. flavus appeared in greater number as compared to other fungi. Similarly, A. candidus was contributed highest percentage followed by A. flavus in dilution plate technique. Total eight species of fungi belonging to three genera were found when soil was treated with cypermethrin at a concentration of 800 ppm. A. candidus and A. flavus were isolated in highest number at 1000ppm cypermethrin. But, in direct plate technique, A. flavus was found to be the dominant species followed by A. terreus and A. niger at 1000 and 1200ppm concentration of cypermethrin, respectively. Soil treated with cypermethrin at 1400ppm concentration exhibited that A. awamori was the dominant species isolated followed by A. terreus and Mucor hiemalis both in direct and dilution plate techniques. Among all the isolates screened for protease activity, A. terreus was potent enough for this production.
Keywords: Aspergillus, cypermethrin, protease, soil.