Selective Medium for Ceratocystis ulmi. R. V. Miller, Department of Plant Pathology, Montana State University, Bozeman 59717. D. C. Sands, and G. A. Strobel, Department of Plant Pathology, Montana State University, Bozeman 59717. Plant Dis. 65:147-149. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-147.

A medium containing linoleic acid, cycloheximide, dicloran, triphenyltin hydroxide, chloramphenicol, and streptomycin sulfate in potato-dextrose agar was developed for selective isolation of Ceratocystis ulmi. The medium facilitated the rapid isolation of C. ulmi from elm tissue and bark beetles. An aggressive isolate of C. ulmi retained pathogenicity after being cultured on the medium, and all isolates of the fungus tested grew on the medium. A strain of C. montia, causal agent of blue stain of conifers, also grew on the selective medium. C. montia, like C. ulmi, forms conidia exogenously; C. fimbriata and C. fagacearum, two species that form conidia endogenously, did not grow on the medium.