Unraveling the semiochemical mediated oviposition behavior of female dogwood borer (Lepidoptera: Sesiidae)

The dogwood borer, Synanthedon scitula (Harris) (Lepidoptera:Sesiidae), is a pest of a wide range of fruit, nut and ornamental trees throughout eastern North America. The olfactory responses of female dogwood borer to host-plant volatiles appear to be an important component of their host-finding and oviposition site selection behaviors. In apple trees on size-controlling rootstocks, burr knots that are often formed below the graft union appear to be attractive oviposition sites for mated female dogwood borer and are typically where infestations originate. Mated female dogwood borer frequently engage in casting flight, probing with the ovipositor, and oviposition below the graft union of trees where burr knots are located. In addition, female dogwood borer antennae possess a greater number of olfactory sensilla than do male antennae. Although electrophysiological bioassays have revealed that both virgin and mated females respond to volatile compounds collected from apple burr knot tissue, our understanding of the stimuli associated with oviposition site selection by mated females remains incomplete. Several behavioral bioassays were conducted to further explore these stimuli and their role in oviposition site selection. However, results from these studies were inconclusive and further research is needed to understand the insect-host plant interactions of female dogwood borer in apple.