Electroantennographic Responses of the Small Chestnut WeevilCurculio sayi(Coleoptera: Curculionidae) to Volatile Organic Compounds Identified From Chestnut Reproductive Plant Tissue

Abstract

The primary insect pest of the developing chestnut industry in the central United States is the small chestnut weevil, Curculio sayi (Gyllenhal), which is a specialist on only Castanea trees. Recent research has shown this insect is attracted to and feeds upon the reproductive tissues of the chestnut tree, including the flowers, burs, and nuts. In this study, the major volatile components emanating from the chestnut's reproductive tissues were sampled using solid phase microextraction and static headspace analysis. In total, 59 compounds from these tissues were separated and identified using GC-MS and authenticated reference standards. The majority of compounds identified from the bur and nut tissues were esters (60.2 and 67.4%, respectively). The majority of compounds identified from catkins were alcohols and benzenoids (53.2 and 19.8%, respectively). A subset of those compounds identified from the chestnut plant tissues was used in electroantennogram testing to determine the insect's electrophysiological response to host-generated volatiles. This study identifies the major components of the volatile profile from several important chestnut plant tissues, and was the first to report the volatile compounds from bur tissue. The identification of the major volatiles emanating from chestnut tissue, as well as the associated insect response, are both critical to the successful utilization of these host-plant volatiles as attractants in the development of a semiochemical-based monitoring trap for C. sayi adults.