Results of trials in walnut orchards of trap types, initial pheromone charges, and effect of field aging on the attractancy to males of Laspeyresia pomonella (L.), of rubber septa having a 1.0 mg initial pheromone charge were as follows: (1) the most suitable trap for codling moth trapping among those tried was the Pherocon IC trap; (2) septa hadng an initial charge of 1.0, 0.1, and 0.01 mg were equally attractive for the 1st 7 days in the field, although the 0.01 mg charge was numerically inferior to the 1.0 and 0.1 mg charges; septa charged with 10 mg were significantly less attractive than septa charged with 1.0 and 0.1 mg charges but not less attractive than septa charged with 0.01 mg; (3) septa that had field-aged for at least 3 wk were significantly less attractive than unaged (fresh) septa; (4) to maintain a trap which would be at least 75% as attractive as a trap with a fresh septum, septa need to be replaced at least on a 12-day basis.