Submitted to: Phytoprotection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2007
Publication Date: 3/18/2008
Citation: Abbas, H.K., Shier, W.T., Cartwright, R.D. 2008. Effect of Planting Date on Aflatoxin and Fumonisin Contamination in Commercial Corn Hybrids in Arkansas. Phytoprotection. 88:41-50 Interpretive Summary: Toxins called aflatoxin and fumonisin, produced by molds Aspergillus and Fusarium species, respectively, are significant problem materials found in corn, especially in the southeastern U.S. Strategies are needed to reduce economic losses caused by this problem. It has been hoped that using corn hybrids with shorter growing seasons would minimize toxin contaminations. This study showed a trend to reduction in both aflatoxin and fumonisin contaminations with earlier planting dates, although use of Bt corn hybrids did not reduce contamination. This information should be useful for corn growers in the southeastern U.S. in selecting a planting time associated with reduced toxin contamination.
Technical Abstract: Corn (maize, Zea mays L.) in the southeastern USA is susceptible to infection by several toxigenic fungi, particularly Aspergillus flavus and Fusarium species, resulting in contamination of the harvested kernels with aflatoxins and fumonisins, respectively. In theory, the development of commercial corn hybrids with shorter growing seasons has made possible a strategy for reducing mycotoxin contamination by selecting planting dates which minimize plant stress during the critical kernel-filling period. To evaluate this strategy, commercial Bt and non-Bt hybrids were planted in Arkansas in April and May of 2002, 2004 and 2005, and allowed to become naturally infected with fungi. Corn kernel samples collected at harvest were assayed for total aflatoxins, total fumonisins and fumonisin types B1, B2, B3, B4, A1 and C1. Planting at the earlier date resulted in harvested corn with lower levels of both aflatoxins and fumonisins during each of the three years and in total, but the difference was statistically significant (P< 0.05, t-test) only for fumonisins for the three years in total (P< 0.05, t-test) and for 2002. Frequent co-occurrence of aflatoxin and fumonisins was observed. Mycotoxin levels were compared with measures of heat stress during the kernel-filling period. Mycotoxin levels in Bt-hybrids were not significantly different from those in non-Bt hybrids.