Effect of Nitrogen Fertilizer, Planting Date, and Harvest Date on Aflatoxin Production in Corn Inoculated with Aspergillus flavus. R. K. Jones, Graduate Research Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650. H. E. Duncan, Professor and Specialist in Charge, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Plant Dis. 65:741-744. Accepted for publication 29 December 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-741.

Concentrations of aflatoxin B₁ were measured in artificially wounded and inoculated kernels of a short-season and a full-season corn cultivar grown in the Tidewater area of North Carolina, where incidence of aflatoxin from natural infection by Aspergillus flavus is low. In 1978, isolate 160 of A. flavus grew well but produced very little aflatoxin in inoculated ears; in 1979, it produced moderate levels while a second isolate, 3357, produced high levels. No significant difference was established between cultivars in either year, but corn planted 9 May 1979 had more aflatoxin than corn planted 11 April 1979. Significantly more aflatoxin was produced in grain harvested late (18% moisture) than in that harvested early (28% moisture). Aflatoxin B₁ concentrations were consistently higher in corn grown in plots low in nitrogen. These results suggest that corn planted and harvested late and produced under nitrogen stress is a better substrate for preharvest aflatoxin production than corn grown under good management practices and supplied with adequate nitrogen.