(1R,6R)-2,2,6-Trimethyl-3-oxabicyclo[4.2.0]octan-4-one, a new monoterpene lactone produced by males of the cocoa borer Conotrachelus humeropictus (Col.: Curculionidae)
The cocoa weevil Conotrachelus humeropictus is an economically most important pest on cocoa (Theobroma cacao) and cupuaçu (Theobroma grandiflorum) cultures. Knowledge on the pheromone system of this insect is prerequisite for the development of an integrated pest management system. GC/MS-analysis of headspace volatiles revealed the presence of three male specific compounds, which were identified to be (1R,2S)-grandisol, (1R,2S)-grandisoic acid, and the new bicyclic terpene lactone (1R,6R)-2,2,6-trimethyl-3-oxabicyclo[4.2.0]octan-4-one, which we term grandisolide.