Cydia pomonella lure is a component of an insect trapping device, that uses pheromones to lure codling moths, that attack apple, pear and walnut crops among others, into a trap. 
The lure, in the form of the rubber dispenser, containing Cydia pomonella pheromone, must be placed in a pheromone trap to be fully functional (traps can be bought separately or in kits with lures). 
Using such pheromone lures is an economic, environmentally sound approach to either monitor or mass-trapp these pests. 
The lures in the traps must be replaced every 4-6 weeks to keep attraction rates high. Shelf life - up to 1 year (optimum conditions).