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A Selective Medium for Isolation of Corynebacterium nebraskense From Soil and Plant Parts. D. C. Gross, Department of Plant Pathology, University of Nebraska, Lincoln 68583; A. K. Vidaver, Department of Plant Pathology, University of Nebraska, Lincoln 68583. Phytopathology 69:82-87. Accepted for publication 2 August 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-82.

A selective agar medium (CNS) was developed for isolating Corynebacterium nebraskense, the causal agent of Gossís wilt, from corn tissue and soil. Selectivity depended on a combination of nalidixic acid, polymyxin B sulfate, lithium chloride, cycloheximide, and Bravo 6Fģ. Recovery of C. nebraskense on CNS from pure culture was equal to the recovery on a nutrient broth-yeast extract medium (NBY). CNS medium was quantitatively and qualitatively superior to other selective media developed for Corynebacterium spp. From soil, C. nebraskense generally could be isolated as low as 103 colony-forming units per gram of soil. More than 99% of the total recoverable soil bacteria on NBY could not grow on CNS. Some coryneform and coccoid soil bacteria grew on CNS. In addition to C. nebraskense, high efficiencies of plating on CNS were noted for some phytopathogenic Corynebacterium spp.; however, C. sepedonicum and C. insidiosum did not grow. Soil and airborne fungi were unable to grow on CNS.

Additional keywords: Gossís wilt, Zea mays.