Flight capacity and trap capture of Eucosma giganteana (Lepidoptera: Pyralidae) in response to congeneric semiochemicals

Silphium is a novel perennial crop being developed for oilseed and biofuel needs in the midwestern US. One of the primary pests in this system is Eucosma giganteana (Lepidoptera: Tortricidae), which is univoltine, with larvae boring into the roots and stems. There is currently a push to develop novel monitoring and behaviorally-based management approaches for this pest. While little is known about the chemical ecology of E. giganteana, many semiochemicals have been identified from other closely related Eucosma species. We tested eight of these compounds, including: (E)-8-dodecenyl acetate and (Z)-9-dodecenyl acetate. The goals of this study were to evaluate whether any of these previously identified compounds could improve capture of E. giganteana when combined with clear sticky cards in the field, and how the flight capacity of E. giganteana was affected by the most and least attractive volatiles. We found that there was significant attraction to (E)-8-dodecenyl acetate, while there was significant repellency to (Z)-9-dodecenyl acetate. On flight mills, we found that E. giganteana flew an average of 24 km in a 24 h period, while long-distance dispersers flew up to 100 km. In the presence of both attractive and repellent semiochemicals, the flight capacity of moths was reduced. These compounds may be useful in behaviorally-based monitoring and management strategies. Overall, our research greatly expands the knowledge on the chemical ecology of E. giganteana and its interactions with Silphium.