Apple maggot fly (Rhagoletis pomonella (Walsh)). This insect pest can be managed nonchemically in backyard orchards by hanging red sphere traps with sticky goo on them. Traps are available from pest management suppliers and from other retailers. Alternatively, insecticide applications at two- to three-week intervals from early to mid-July to mid- to late August will prevent the damage.
Contact your local Extension office for information on disease and insect control on backyard fruit plantings.