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Geographical Localization and Lint Fluorescence in Relation to Aflatoxin Production in Aspergillus flavus-Infected Cottonseed. D. E. Gardner, Western Cotton Research Laboratory, ARS, USDA, Phoenix, Arizona 85040, Present address of senior author: National Park Service, Mississippi Test Facility, Bay Saint Louis 39520; J. L. McMeans(2), C. M. Brown(3), R. M. Bilbrey(4), and L. L. Parker(5). (2)(4)(5)Western Cotton Research Laboratory, ARS, USDA, Phoenix, Arizona 85040; (3)Imperial Valley Conservation Research Center, ARS, USDA, Brawley, California 92227. Phytopathology 64:452-455. Accepted for publication 23 September 1973. DOI: 10.1094/Phyto-64-452.

Aspergillus flavus boll infection in specific western regions of the cotton belt results in a characteristic greenish-yellow lint fluorescence often accompanied by aflatoxin accumulation in the seed. However, essentially no aflatoxin or fluorescence have been detected in cottonseed grown at Safford, Arizona; although most A. flavus isolates from infected seed produced aflatoxins in the laboratory. Natural A. flavus infection probably occurs in nondamaged bolls only as bolls open at maturity. At Phoenix, Arizona, and Brawley, California, opening coincided with extended periods of elevated temp. At Safford, most bolls opened during periods of lower temp. A. flavus boll inoculation during the boll-opening period at each location resulted in high infection, aflatoxin, and fluorescence levels at Phoenix and Brawley and also at Safford in August. However, no more than traces of aflatoxin or fluorescence resulted from inoculation-induced infection at Safford in September when the majority of bolls at that location opened. Low temp is suggested as the principal factor limiting aflatoxin accumulation at Safford. Considerable amounts of aflatoxin were detected throughout this study in seed from inoculated bolls containing no fluorescent lint; a significant exception to the usual association of fluorescence with high aflatoxin levels in cottonseed.