Traditional alternatives to chemical pesticides include mechanical and physical controls, such as netting or screen covering, which act as a barrier against pest infestation. By planting resistant varieties, growers are able to control some pests with little or no chemical inputs. At present, there are fourteen named varieties of disease-resistant apple available for implementation or adoption by growers. The four most promising resistant varieties for commercial use are Redfree, Liberty, Freedom, and Nova Easygro. Rootstock varieties resistant to woolly apple aphids are commercially available as well.
Biological control is another alternative.
Some natural chemicals are not used as a pesticide but nonetheless have an important role in pest control. For instance, sex pheromones are used not to kill an insect but to disrupt its mating behavior, thereby decreasing future pest populations. The IGR Dimilin has been tested for more than ten years. Although this material is active against leafminers, for instance, at the same time it is compatible with biological control of mites. Dimilin has been a part of IPM fruit programs in Europe for many years, but it is unclear whether the EPA will approve this IGR for use in the United States because of its effects on aquatic arthropods.