Phytotoxicity of five substituted urea herbicides 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), 3-phenyl-1,1-dimethylurea (fenuron), 3-hexahydro-4,7-methanoindan-5-yl) −1,1-dimethylurea (norea), and 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron) at 0, 10, 100, and 1000 ppm were determined in factorial combination at four urea nitrogen levels of 0, 45, 450, and 900 ppm with three Aspergilli: A. niger, A. sydowi, and A. tamarii. Response interactions were apparent, with all three fungi most tolerant for fenuron and least for diuron. Apparent tolerance order of the three intermediates were: A. niger, norea > fluometuron > monuron; A. sydowi, fluometuron > monuron > norea; and A. tamarii, fluometuron > norea > monuron. Oat (Avena sativa L.) bioassay for residual herbicide toxicity indicated significant differences in herbicide degradation rates between these three fungi at 5, 10, and 20 ppm in Eufaula sand. Diuron was more rapidly degraded than monuron at these levels with fluometuron and norea somewhat intermediate. A. niger was most effective in degradation of these herbicides with A. tamarii greater than A. sydowi. High nitrogen levels in soil organic matter amendment generally favored increased rates of urea herbicide degradation.

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Aspergillus niger van Tieghem, Aspergillus tamarii Kita, and Aspergillus flavus Link ex Fries utilized the methylthio moiety of 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne) as a sulfur nutrient source. Other soil fungal isolates not affected by prometryne concentrations to 1 mg/ml culture included: Aspergillus oryzae (Ahlburg) Cohn, Curvularia lunata (Wakker) Boedijn, Trichoderma viride Persoon ex Fries, Alternaria tenuis Nees ex Corda, Penicillium funiculosum Thom, and Paecilomyces varioti Bainier.