Shelf life studies of pheromone of Helicoverpa armigera (Hübner) at different temperatures and time intervals

The shelf life of septa impregnated with pheromone component (hexadecenol) and 97.3 blend of Z-11-hexadecenal and Z-9-hexadecenal were studied by gas chromatographic estimation of the residual amount of pheromone remaining on the septa after incubation for different time intervals, varying tempertaures and storage conditions. No losses were observed up to 8 weeks from the pheromone blend impregnated glass vials stored in freezer (−10°C) or in fridge (5°C). There was 22% loss of pheromone blend when the vials were stored at room temperature loss of approximate 12% with closed caps and 24% with open caps was observed after 16 weeks. When pheromone component (HDOL) was loded on rubber septa, there was a drastic loss during storage at room temperature just after one week and it further decreased after second week, comparatively less loss was observed during storage in fridge and freezer. These results clearly showed that the pheromone blend/component impregnated glass vials may be stored in fridge or freezer and were better for storage as compared to rubber septum.