Susceptibility of commercial corn hybrids to aflatoxin contamination in Louisiana.

Susceptibility of commercial corn (Zea mays L.) hybrids to aflatoxin contamination was determined at Winnsboro, Louisiana in 1997 and 1998. Thirty-three hybrids were inoculated with 106 conidia/ml of Aspergillus flavus 20 days after midsilk using the pinbar technique. All corn hybrids grown in Louisiana were susceptible to A. flavus and aflatoxin contamination in the field, but differences were detected among hybrids. When averaged across 1997 and 1998, levels of aflatoxin were highest in DeKalb 683 (26,854 ng/g) and Mycogen 2725 (25,254 ng/g) and lowest in Terra TR1185 (3,967 ng/g), Terra TR1167 (5,104 ng/g), Asgrow RX 938 (5,112 ng/g), Terra TR 1226 (5,540 ng/g), Pioneer 3394 (6,354 ng/g), and Pioneer 3167 (7,174 ng/g). This study documents the extreme susceptibility of commercial corn hybrids grown in the southern United States and demonstrates the need for continued research to identify host plant resistance.