Submitted to: Agricultural and Forest Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2011
Publication Date: 1/16/2012
Citation: Brown, M.W. 2012. Role of biodiversity in integrated fruit production in eastern North American orchards. Agricultural and Forest Entomology. 14:89-99. Interpretive Summary: The reduction in the use of chemical insecticides in food production is a goal for both consumers and producers. To control insect pests a replacement to insecticides must be found to allow production of high quality fruit and high yields. In this study reduced insecticide use was replaced with the use of companion plants and interplanted peach trees to provide alternative resources for natural enemies. It was found that even with a reduction of standard insecticides from 4 to 9 applications to one, plus 3 applications of organically approved natural insecticides, fruit damage from insects was equal and yield was similar to standard management practices. Only the late season cultivar Granny Smith had slightly higher levels of insect damage in the experimental orchard. This study showed that there are options to the production of high quality fruit with high yield without high levels of chemical insecticides. These results will be used by fruit production scientists, extension specialists and farmers, both organic and conventional.
Technical Abstract: Diversifying agricultural ecosystems to enhance biological control is a promising way to promote sustainable pest management. Orchards are a good system to study the role of ecosystem services due to their relative permanency compared to other agricultural systems. In this study I combined flowering companion plants with interplanted fruit trees bearing extrafloral nectaries into an apple orchard to provide resources for a more diverse arthropod community and to stimulate the ecosystem service of pest suppression. Monoculture apple and peach with standard insecticide treatments were compared with 3 biodiverse treatments (polyculure, monoculture with companion plants and polyculture with companion plants) with reduced standard insecticide use. Abundance of insect predators was increased by both the presence of companion plants and extrafloral nectar but parasitism rates of the leafroller, Platynota idaeusalis, were not affected. After three years of increased biodiversity there were significant differences in food web structure in the orchard block with both companion plants and extrafloral nectar. There were no consistent effects of biodiversity treatment on either tree growth or fruit yield. Insect injury to Empire apple and peach fruit was not consistently affected by the biodiversity treatments. Granny Smith apples did have higher levels of fruit injury in the biodiverse, low-insecticide treatments because of their late harvest date and the loss of floral and extrafloral nectar resources in early autumn. A reduction in pesticides with added biodiversity proved to be a viable alternative to standard chemical insecticide management for temperate tree fruit. Growth and yield of fruit trees and insect injury to peach and apple fruit were maintained at levels equal to standard chemically-based pest management.