Compounds modifying male responsiveness to main female sex pheromone component of the currant borer,Synanthedon tipuliformis clerk (Lepidoptera: Sesiidae) under field conditions

Abstract

Various blends of (E,Z)-2,13-octadecadien-1-ol acetate (E,Z2,13-18: OAc), (Z)-13-octadecen-1-ol acetate (ZOAc) (two previously identified pheromone components of the currant borer,Synanthedon tipuliformis females), (E,Z)-, (Z,Z)-3,13-octadecadien-1-ol acetates (E,Z- andZ,Z3,13-18:OAc), andZ,Z-3,13-octadecadien-1-ol (Z,Z3,13-18:OH) were evaluated in field traps in three geographic regions. MaleS. tipuliformis were attracted toE,Z2,13-18:OAc in Tasmania, New Zealand, and Hungary. Captures were not influenced by the addition ofZ13-18: OAc, tested in Tasmania and Hungary. In Hungary and New Zealand, the addition ofE,Z3,13-18: OAc toE,Z2,13-18:OAc in a ratio of 100:3 was strongly synergistic; however, in Tasmania captures were reduced. The addition ofZ,Z3,13-18: OAc toE,Z2,13-18:OAc in a ratio of 10∶1 resulted in strong inhibition of trap captures in Hungary. WhenZ,Z3,13-18: OAc was added in different ratios to a 100:3 binary mixture ofE,Z2,13-18:OAc/E,Z3,13-18:OAc in Hungary, it strongly reduced captures at, or above a ratio of 100∶3∶3 but no decrease was recorded at a ratio of 100∶3∶1. In New Zealand and Tasmania it reduced captures at a ratio of 100∶3∶1. Observations of behavioral responses of maleS. tipuliformis in Hungary to synthetic baits in the field showed thatE,Z2,13-18:OAcby itself evoked close-range approaches to the source from only 20% of males, whereas the addition ofE,Z3,13-18:OAc in a ratio of 100∶3 raised that value to 65 %. Landing on the source was significant only at sources with a 100∶3∶0.1∶3∶10 blend ofE,Z2,13-18:OAc/E,Z3,13-18: OAc/Z,Z3,13-18: OAc/Z,Z3,13-18: OH/Z13-18: OAc. A 100∶3 binary mixture ofE,Z2,13-18:OAc/E,Z3,13-18:OAc in a dose range of 10-1000 μg can be recommended for more effective field monitoring ofS. tipuliformis populations in Hungary and in New Zealand. In Tasmania, at present,E,Z2,13-18: OAc by itself is the most potent sex attractant of the species.