Volatile Byproducts of Carotenoid Degradation as Biomarkers of Maize Infestation by the Maize Weevil (<i>Sitophilus zeamais</i>) (Motsch.)

Maize (<i>Zea mays</i>) is a major global food crop and a source of industrial raw materials. Effective postharvest storage is important for national food security programs, international trade, and global agriculture economics. The maize weevil (<i>Sitophilus zeamais</i>) is a primary postharvest insect pest that infests maize during storage and leads to significant losses. Using multivariate discriminant analysis of volatile profiles collected from intact and infested maize, we identified two volatile apocarotenoids, 6-methyl-5-hepten-2-one and 6-methyl-5-hepten-2-ol, as indicators of maize weevil infestation in stored maize. Emission of these biomarker compounds rapidly signaled maize weevil infestation and showed a significant correlation with oviposition damage to the stored kernels. The pattern of elevated biomarker emission after weevil exposure was consistent across all seven maize lines examined. These volatile biomarkers can be used for early detection and removal of infested maize and can aid in the control of this pest.