Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2004
Publication Date: 6/1/2004
Citation: Chapin, J.W., Dorner, J.W., Thomas, J.S. 2004. Association of a burrower bug, pangaeus bilineatus (say) (heteroptera: cynidae) with aflatoxin contamination of peanut kernels. Journal of Entomological Science. 39:71-83. Interpretive Summary: Aflatoxin contamination of peanuts compromises the safety of food and feed supplies and causes significant economic losses each year. Aflatoxin contamination can occur when peanuts are infected with aflatoxin-producing strains of Aspergillus flavus and A. parasiticus, molds that are relatively abundant in agricultural soils. This study showed that aflatoxin contamination of peanuts was associated with feeding by a burrower bug, Pangaeus bilineatus (Say), which can be found in soil. When peanut kernels from a drought stressed field were separated on the basis of visual evidence of burrower bug feeding, kernels with visible feeding sites had significantly higher levels of aflatoxin than did kernels without feeding sites. In the samples of peanuts analyzed, almost all of the aflatoxin was associated with burrower bug feeding. Although aflatoxin contamination of peanuts can occur without burrower bug damage, this study demonstrates an increased risk of contamination in peanuts from fields with burrower bug infestation. Growers should consider this risk and take steps, such as appropriate insect control measures, to prevent increased aflatoxin contamination resulting from burrower bug damage.
Technical Abstract: Aflatoxin contamination of peanut kernels, Arachis hypogaea L., was associated with feeding by a burrower bug, Pangaeus bilineatus (Say). Kernel samples were divided into three grade categories: total mature kernels (TMK), other kernels (OK), and damaged kernels (DK); and each of these grade categories was subdivided based on evidence of burrower bug feeding. Within TMK, 100% of detectable aflatoxin contamination was associated with kernel feeding and fed-on kernels had a significantly higher concentration of aflatoxin than kernels without feeding sites (7.5 vs. 0.0 ppb). Within the OK grade category, differences in aflatoxin contamination were not significant due to the inability to conclusively examine these kernels for feeding sites. Within the DK grade category, aflatoxin concentration was significantly higher in fed-on kernels than in kernels without observable feeding sites (286.5 vs. 0.4 ppb) and 99.9% of contamination was associated with burrower bug feeding. Across all grade categories, aflatoxin levels were 65 times higher in kernels with observable burrower bug feeding, and on average, 93% of all aflatoxin contamination was associated with burrower bug feeding. The DK grade category had the highest concentration of aflatoxin and accounted for 51% of total contamination. Burrower bug-induced aflatoxin contamination of the TMK grade category is particularly significant because this source would be most difficult to remove from the food supply. Contamination of the DK category is also economically significant because this grade component is specifically examined for Aspergillus at the buying point, and growers are severely penalized for detection.