Organic Orchard Management: Organic Orchard Design
Orchard design and cultivar selection have a long-term impact on pest control. While apple trees are resilient and can usually survive for decades without human intervention, year-round migration of pests from wild or unmanaged apple trees almost guarantee pest damage to unsprayed fruit. Surveys have shown that more than 95% of the fruit on wild or abandoned apple trees are usually damaged or infested.
Some specific organic pest control methods are more effective when there are fewer orchard edges bordering natural areas or unmanaged orchards. For example, pheromone mating disruption is much less effective in apple orchards where mated female codling moths, oriental fruit moths, or apple maggots can easily fly into the orchard from surrounding areas. In some situations, growers may want to selectively remove unmanaged trees that are closely related or a host for other pests of the fruit crop. For example, apple pests may move from crabapple trees, hawthorns, cedar, juniper, mountain ash, cotoneaster, and quince. To minimize migration of pests, these species would need to be removed within a minimum of a half-mile of the orchard.
Edge habitats can be beneficial for wildlife biodiversity by providing habitat for beneficial insects. They also act as a tool in resistance management of key insect pests, such as codling moth, peach twig borer, or western cherry fruit fly as wild-type individuals from surrounding habitat migrate into your orchard and mate with the resident pest population. Having these two gene pools intermix will help delay the development of pesticide-resistant pests.