The Influence of the Use of Pesticides on Principal Groups of Microorganisms Present in the Eutric Cambisol

To produce a healthy and vigorous afforestation material, besides the technical works are needed measures to prevent and control the pathogenic agents presents in forestry crops. Pest control and pesticide management are integral parts of the best management practices during the growing period of nursery crops. Pesticides used in nursery settings should be selected not only to control the pest, but also to limit its ability to negatively impact the environment. The objective of this investigation was to determine the effects of the fungicide Microthiol on principal groups of microorganisms determined in eutric cambisol collected from a nursery. The fungicide was applied at recommended dosages. The effects of this pesticide on total viable bacteria were investigated in laboratory experiments. Enumeration of total number of microorganisms, Actinomycetes, yeast-mold, nitrogen fixing bacteria and nitrifying bacteria was accomplished by serial dilution and plate count technique or most probable number method. Based on the obtained results, was calculated the bacterial indicator of the soil quality (BISQ). The results were analyzed with the "Student" test used to determine the significance or non-significance of differences between the values. The statistical interpretation of the results suggest that the fungicide Microthiol had no influence on the physical and chemical properties of the eutric cambisol and also there were no significant differences between the untreated and treated soil variant. The microorganisms are capable to grow in the presence of several commercial pesticides. Catabolism and detoxification metabolism occur when a soil microorganism uses the pesticide as a carbon and energy source