VIEW ARTICLE

Etiology

Soybean Seed Lot Contamination by Melanopsichium pennsylvanicum Smut Galls. C. T. Schiller, Former graduate research assistant, department of Plant Pathology, University of Illinois, Urbana, 61801, Senior author’s present address: Mobay Chemical Corp., 619 Normandie, Bowling Green, OH 43402; J. B. Sinclair, professor, department of Plant Pathology, University of Illinois, Urbana, 61801, Senior author present address: Mobay Chemical Corp., 619 Normandie, Bowling Green, OH 43402. Phytopathology 69:605-608. Accepted for publication 21 December 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-605.

Smut galls were found in a soybean (Glycine max ‘Williams’) seed lot harvested from a field near Jerseyville, IL in 1977. The galls were determined to be smut-infected inflorescences of smartweed (Polygonum pennsylvanicum). The smut fungus was identified as Melanopsichium pennsylvanicum; this fungus previously had been identified as the causal agent of a smut of soybean, M. missouriense. The Jerseyville specimen was compared to herbarium specimens of M. pennsylvanicum on P. pennsylvanicum from the Illinois State Natural History Survey (ILLS), Urbana, and the type specimen of M. missouriense obtained from the National Fungus Collections, Beltsville, MD. It was compared also to fresh material from smartweed plants wound-inoculated with M. pennsylvanicum chlamydospores from the Jerseyville specimen. Gall and chlamydospore morphology was similar for all specimens. All wound-inoculated smartweed plants developed galls. Symptoms did not develop on soybean plants inoculated with chlamydospores of M. pennsylvanicum. Scanning electron micrographs of chlamydospores showed variation in the wall ornamentation of some chlamydospores in the ILLS specimen. Based on the above comparisons, we consider M. pennsylvanicum and M. missouriense to be synonymous.