Fungal Biodegradation of Organophosphorus Insecticides and their Impact on Soil Microbial Population

Impact of organophosphrus insecticides Malathion Profenofos and Diazinon were assessed on soil microbial populations. The degradation characteristics of these organophosphrus insecticides at different concentrations, incubation periods and temperature by an isolated fungal strains Trichoderma harzianum and Metarhizium anisopliae were investigated. Fungal population was reduced by 56.37, 51.07 and 26.65% at 10 day of application by profenofos, diazinon and malathion respectively, compared to the control. Fungal degradion of profenofos , diazinon and malathion increased with increasing incubation peroid but at the same time decreased with increasing initial concentrations of insecticides. Using M. anisopliae, almost 85.60, 77.20 and 68.15% of initial diazinon was decomposed within 20 days at 10, 20 and 40 mg of diazinon, while profenofos was degraded with 54.70, 62.45 and 63.68 at 20 days at 10, 20 and 40 mg. At 20 mg of initial malathion, more than 90% of the initial concentration was degraded by M. anisopliae. After 10 days of incubation, the degradationpercentage of diazinon at 20, 25, 30, 35 and 40C was examined to be 17. 85, 35.38, 43.45, 33.85, and 7.80%, while degradationpercentage of Profenofos was examined to be 13.60, 30.35, 35.43, 30.10 and 7.56% respectively, similar results of malathion degradationpercentage were obtained to be 44. 78, 50.65, 60.58, 57.73 and 10.28% at 20, 25, 30, 35 and 40C respectively with using M. anisopliae. Degradationpercentage at 35C was 1.90, 2.21 and 1.29 time fasters for diazinon, profenofos and malathion resppectively than those at 20C with using M. anisopliae. While degradationpercentage at 35C was 2.07, 1.72 and 1.83 times fasters for diazinon , profenofos and malathion resppectively than those at 20C with using T. harizianum. On the basis of present findings, these fungal strains can be recommended as potentially effective to protect the environment from the organophosphorus insecticides residues.