VIEW ARTICLE

Disease Detection and Losses

Effect of Temperature on the Preharvest Infection of Maize Kernels by Aspergillus flavus. G. A. Payne, Associate professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616; D. L. Thompson(2), E. B. Lillehoj(3), M. S. Zuber(4), and C. R. Adkins(5). (2)Professor emeritus, Crop Science Department, North Carolina State University, Raleigh 27695-7616; (3)Research scientist, Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, New Orleans, LA 70179; (4)Professor emeritus, Agronomy Department, University of Missouri, Columbia 65211; (5)Research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Phytopathology 78:1376-1380. Accepted for publication 7 June 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1376.

The effect of temperature on colonization of maize silks and the subsequent invasion of kernels by Aspergillus flavus was studied in controlled environments. At the postinoculation temperature regimes of 34/30 C (34 C × 9 hr, 30 C × 15 hr) and 26/22 C, as many as 28 and 2.4% of the kernels, respectively, were infected. Infected kernels were present in all areas of the ear, and neither temperature nor time of inoculation affected the location of infected kernels on the ear. At 34/30 C the fungus entered the ear tip in one day and was present in the base by 4 days. Internal infection of the ear did not occur until 8 days after inoculation, and the percentage of infected kernels increased greatly between 28–32 days, when kernel moisture was <32%. These results demonstrate that the parasitic ability of A. flavus is enhanced at high temperature and that, although surface colonization of the kernels occurs early, extensive internal infection does not occur until kernel maturity.