Effects of Irrigation and Kernel Injury on Aflatoxin B₁ Production in Selected Maize Hybrids. B. A. Fortnum, Associate Professor, Clemson University, Pee Dee Research and Education Center, Florence, SC 29503. A. Manwiller, Professor Emeritus, Clemson University, Pee Dee Research and Education Center, Florence, SC 29503. Plant Dis. 69:262-265. Accepted for publication 21 September 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-262.

Effects of irrigation, simulated corn earworm (SCEW) damage, and naturally occurring insect damage on aflatoxin B₁ production in 15 selected maize hybrids were evaluated during 1979 and 1980. Aflatoxin production in preharvest maize among the hybrids attained levels ranging from 8,966 to 70,809 ppb in treatments receiving SCEW damage and Aspergillus flavus inoculation. Aflatoxin levels in hybrids inoculated with A. flavus without SCEW damage ranged from 32 to 1,863 ppb. Natural infection resulted in aflatoxin levels of 2–605 ppb. Irrigation suppressed aflatoxin production in kernels receiving both SCEW damage and A. flavus inoculation. Insect damage correlated (P = 0.01) with preharvest aflatoxin levels when averaged over hybrids and maturity groups for 1979 (r = 0.50) and 1980 (r = 0.73). Grain from inoculated and uninoculated maize hybrids varied significantly in levels of preharvest aflatoxin. There was little agreement between 1979 and 1980, however, suggesting strong environmental effects on aflatoxin production.