A survey of the parasitism of twig-feeding larvae and fruit infestation was made in a number of New Jersey orchards from 1937 to 1939 inclusive. A high degree of parasitism of the first 2 broods of larvae was found in the majority of orchards in each of the 3 yrs. In southern New Jersey the principal parasite found was Macrocentrus ancylivorus and in northern New Jersey Glypta rufiscutellaris. Fruit infestation in each of the 3 yrs. was light to moderate on vars. ripening during the Elberta season in the majority of the orchards. No strict correlation was found between either % total parasitism or 2d brood parasitism and % fruit infestation. A correlation was found between the nature of the planting and the % fruit infestation. Orchards in which late ripening vars. were interplanted with early and midseason ripening vars. of peaches showed high fruit infestation counts on the late ripening vars. Blocks planted solid to late ripening vars. showed the lowest fruit infestation.