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Pink Seed of Wheat Caused by Erwinia rhapontici in Idaho. R. L. Forster, Department of Plant, Soil, and Entomological Sciences, University of Idaho, Kimberly 83341. J. F. Bradbury, CAB International Mycological Institute, Kew, England. Plant Dis. 74:81. Accepted for publication 5 September 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0081C.

Pink seed, caused by Erwinia rhapontici (Millard) Burkholder, was detected for the first time in Idaho (and for only the second time in the United States [1]) in wheat (Triticum aestivum L.) cultivar Penewawa in 1987. Affected seeds from plants produced under sprinkler irrigation in Bingham County had a distinct pink appearance when compared with healthy seed and were slightly shrunken. The causal organism was isolated on yeast-dextrose-calcium carbonate agar, in which it prod uced a pink diffusible pigment. According to the results of standard physiological and biochemical tests, the organism belonged to the family Enterobacteriaceae. Our strains were similar to those examined by Roberts (2) except that ours did not produce acid from lactose. Pathogenicity was confirmed by Roberts's method (2), and the pathogen was reisolated from mature wheat kernels but not from the un inoculated check. A culture has been deposited in the NCPPB, Plant Pathology Laboratory, Hatching Green, Harpenden, Hertfordshire, England.

References: (1) M. P. McMullen. Proc. N.D. Acad. Sci. 38:78, 1984. (2) P. Roberts. J. Appl. Bacteriol. 37:353, 1974.