Max-Planck-Institut Seewiesen, 82319 Starnberg, Germany.
The synthetic pheromone of the European grape moth Lobesia botrana was heated to 100°C and exposed to UV light (302 nm). It was examined before and after degradation by means of a GC-MS(D) and tested for its attractivity by field trapping. The degradation products of the irradiated samples did not attract L. botrana. Some of the traps did attract insects belonging to other species (Cydia pomonella, Lymantria dispar). The structure of several degradation products was discussed. It turned out that oxidative together with thermal processes are involved in the observed pheromone degradation. Unlike the pheromone of L. botrana with conjugated double bonds, the synthetic pheromone components of three other moth species without conjugated double bonds showed under the same conditions a good stability.