Submitted to: Multicrop Aflatoxin and Fumonisin Elimination and Fungal Genomics Workshop-The Peanut Foundation
Publication Type: Abstract Only
Publication Acceptance Date: 10/17/2005
Publication Date: 10/17/2005
Citation: Krakowsky, M.D., Ni, X., Davis, R.F., Da, K. 2005. Correlation between biotic stresses and aflatoxin contamination in maize [abstract]. In: Proceedings of the Multicrop Aflatoxin and Fumonisin Elimination and Fungal Genomics Workshop, October 23-26, 2005, Raleigh, NC. p. 121. Interpretive Summary: not required
Technical Abstract: Aflatoxin, a toxin produced by the fungus Aspergillus flavus, is the most potent carcinogen found in nature. Aflatoxin contamination of maize is a chronic problem in the southern US, where high temperatures, water stress, and insect damage produce conditions conducive to infection of maize by A. flavus. The purpose of this research was to determine the relationship between three biotic stresses, leaf feeding by the fall armyworm (FAW), Spodoptera frugiperda, ear feeding by the Stink bug, and root feeding by the root-knot nematode (RKN), Meloidogyne incognita, and contamination of grain with aflatoxin. In the first experiment, five hybrids (four commercial and one aflatoxin resistant) were grown in a split-plot design with whole plots representing FAW artificially-infested or non-infested conditions and split-plots representing a hybrid. FAW damage was evaluated at seven and fourteen days after infestation. In the second experiment, stink bug damage were evaluated both under natural and artificial infestation, the former utilizing a field planted solid with a single hybrid and divided into grids, and the later utilizing both individual ear cages and larger, plot-size cages to evaluate different insect populations. In the third experiment, three commercial hybrids were grown in a randomized complete-block design in a field with high population densities of RKN. A fumigant nematicide was used to create plots with minimal nematode damage to compare to non-fumigated plots with a high level of nematode damage. Early (pre-plant), mid, and late (at harvest) season nematode population levels were estimated based on soil samples. Correlations between plant damage, plant stress, and yield and aflatoxin contamination can be used to evaluate the significance of particular biotic stresses on aflatoxin contamination of maize and determine the focus of genetic improvement and crop management programs.