MARIOARA NICOLETA FILIMON, ROXANA POPESCU, DOINA VERDES, GABI DUMITRESCU, OCTAVIAN SORIN VOIA, MIRELA AHMADI, DOREL DRONCA THE EFFECTS OF DIFENOCONAZOLE TREATMENT ON MICROORGANISM FROM SOIL The present study quantified the effect of difenoconazole (DFC) on bacteria and mold communities grown in laboratory conditions, in treated soil microcosms difenoconazole, using the following concentrations: control, half dose (0.037 mg DFC / g soil, HD), normal dose (0.075 mg DFC / g soil, ND) and double dose (0.150 mg DFC / g soil, DD). The microbiological analysis included mesophilic bacteria involved in the nitrogen cycle: aerobic and anaerobic nitrogen-fixing, ammonifying, nitrifying and denitrifying bacteria. The mesophilic bacteria were incubated at 37°C and identified qualitatively on solid growth medium (Nutrient agar), whereas soil fungi were identified both quantitatively and qualitatively on solid growth medium (Potato-Glucose-Agar). In high doses, the DFC decreased the microbial communities involved in nitrogen cycle, namely aerobic and anaerobic bacteria and denitrifying bacteria. Noticeable was the response of two genera, namely Mucor sp. and Actinomucor sp., that showed resistance to the toxic effect of DFC, underlying their potential further practical use in the decontamination of polluted soils.