The effectiveness of codling moth,Laspeyresia ponmnella(L.), control by the sterile-insect release method depends on the frequency of effective matings between the released sterile males and the wild females (Proverbs 1971). The higher the frequency of this mating, relative to the matings between the wild males and wild females, the more sterility is introduced into the wild population; this applies irrespective of whether only sterile males or sterile males and females are used for release.