Botryodiplodia hypodermia and Tubercularia ulmea in Cankers on Siberian Elm in Northern Great Plains Windbreaks. J. M. Krupinsky, Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Northern Great Plains Research Center, Mandan, ND 58554. Plant Dis. 65:677-678. Accepted for publication 18 December 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-677.

Cankers were collected from Siberian elms in 56 counties in Minnesota, Montana, North Dakota, and South Dakota. Of 609 cankers analyzed for fungi, 66% were small branch, 29% were basal, and 5% were large branch cankers. Botryodiplodia hypodermia, Tubercularia ulmea, Cytospora sp., and other fungi were recovered from 42, 17, 28, and 13% of the cankers, respectively. Cankers developed only on trees inoculated with B. hypodermia and T. ulmea. B. hypodermia was the most important pathogen. T. ulmea was isolated from only 17% of the cankers, and 82% of these were small branch cankers.