Mating disruption dispensers work by releasing synthetic pheromone which prevents or delays males from finding and mating with females. Therefore, dispensers need to be placed in your orchard before the first moths fly and mate. First moth flight (= biofix) occurs at around 175 DD. We recommend to place pheromone traps before first apple blossoms open or by 100 DD whichever comes first.
Links
Orchard Pest Management Online – Mating disruption Read PMTP Newsletter – Codling moth mating disruption