The lesser chestnut weevil, Curculio sayi (Gyllenhal), is a key pest of chestnut in the eastern and central United States. Y-tube bioassays and electroantennogram (EAG) studies were conducted on adult C. sayi regarding their behavioral and EAG responses towards odors from different chestnut tissue types (leaf, catkin, bur and nut) to determine the possibility of using host-plant volatiles in monitoring this highly host-specific pest. In behavioral trials, spring emerging weevils (of both sexes) were significantly attracted to odors emanating from catkins (flowers) and burs, with males also attracted to the odors from the nut. In the late-summer, weevils (of both sexes) emerging or returning to chestnut trees were again significantly attracted to the odors from bur and catkin tissues, with females also being attracted nut tissue. Odors emanating from leaves were not attractive to either sex. The EAG trials revealed that weevil antennae responded significantly to odors from bur spikes and the inner bur tissue layer, as well as to odors from catkin and leaf tissues; however, the weevils (regardless of sex or season of collection) were not significantly responsive in EAG tests to odors from the nut tissue (site of oviposition). This study provides key initial data that strongly suggests that chestnut plant volatiles can be successfully utilized as attractants in a semiochemical-based monitoring trap for C. sayi adults.
volatile organic compound (VOC)