Prolonged slow release of (Z)-11-hexadecenyl acetate employing polyurea microcapsules

The potential use of polyurea microcapsules, as 'release carriers' for insect pheromones, has been demonstrated. (Z)-11-hexadecenyl acetate (Z11-16:Ac), the major sex pheromone component of several Noctuidae species, was used as the model molecule. The coating material's ability to release the pheromone was initially studied by the solid-phase micro-extraction technique. Polyurea microcapsules released Z11-16:Ac relatively slowly, with a duration of approximately 1 month, as it was determined under both laboratory and semi-field conditions. Preliminary laboratory bioassays revealed a satisfactory attraction of Sesamia males, at doses of 50 and 500 mg of dried microcapsules containing the aforementioned pheromone. Almost all male insects tested initiated flight and among them 40.2-49.4% successfully contacted the pheromone source. The preparation of polyurea microcapsules needs further refinement as to increase release duration; nevertheless, these results demonstrate strong potential for the future use of polyurea microcapsules as part of integrated insect control programmes.