VIEW ARTICLE

Influence of Diurnal Temperature Cycles on Infection of Cotton Bolls by Aspergillus flavus. R. G. Gilbert, Research Microbiologist, U.S. Water Conservation Laboratory and Western Cotton Research Laboratory, Phoeniz, AZ 85040; J. L. McMeans(2), and R. L. McDonald(3). (2)(3)Plant Physiologist, and Biological Science Technician, respectively, U.S. Water Conservation Laboratory and Western Cotton Research Laboratory, Phoeniz, AZ 85040. Phytopathology 65:1043-1044. DOI: 10.1094/Phyto-65-1043.

Excised cotton bolls were inoculated with an aflatoxin-producing strain of Aspergillus flavus (ATCC #26994), and were placed in growth chambers for 7 or 3 days with short (2-hour) or long (10-hour) diurnal maximum temperature cycles. The maximum and minimum temperatures were 30-32 C and 16-18 C, respectively. The percent bright greenish-yellow (BGY) fluorescence of locks and seeds, as well as seed infection of BGY-fluorescent seeds, increased as the duration of the daily maximum temperature of 30 C increased, and/or as the number of diurnal maximum temperature cycles of 30 C increased. Aflatoxin did not accumulate in A. flavus-infected seed, regardless of treatment.