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NonInterference of Pseudomonas in the Bright, Greenish-Yellow (BGY) Fiber-Fluorescence Test for Aspergillus flavus Boll Rot. Paul B. Marsh, Plant Physiologist, Nutrition Institute, Agricultural Research Service, USDA, Beltsville, Maryland 20705; Marion E. Simpson(2), and George V. Merola(3). (2)(3)Plant Pathologist, and Chemist, respectively, Nutrition Institute, Agricultural Research Service, USDA, Beltsville, Maryland 20705. Phytopathology 64:326-328. Accepted for publication 31 August 1973. DOI: 10.1094/Phyto-64-326.

Bright, greenish-yellow (BGY) fluorescence in raw cotton fiber is used to detect Aspergillus flavus boll rot. However, it was reported recently that Pseudomonas infection can also cause “yellow-to-green” fluorescence in cotton fiber in the field. Evidence indicates that, under the conditions used in our laboratory, Pseudomonas infection probably has caused few if any false positives in the BGY-fluorescence test. BGY-fluorescing fiber of commercial origin has been found consistently in our laboratory (1) to contain a fluorescing pigment chromatographically identifiable with a pigment produced by A. flavus on cotton fiber in pure culture and (ii) to be infected with A. flavus but not to be infected with Pseudomonas. In any case of doubt concerning recognition of the A. flavus-BGY-fluorescence, its identity can be checked quickly by the simple tests described here.

Additional keywords: aflatoxins, Gossypium hirsutum L., survey.