Ecosystem effects of a conservation biocontrol experiment in an eastern orchard

Flowering plants (buckwheat, marigold, dill and purple tansy) and interplanting of peach trees with apple trees were tested to increase biological control in apple and peach orchards in eastern West Virginia. In addition to rates of biological control; pest populations, natural enemy populations, biodiversity, insect damage to fruit and yield were measured. There were no detectable changes in biological control or arthropod biodiversity as a result of the experiment. However, population levels of some pests and percent fruit damaged by several insect pests was affected by increasing plant diversity of the orchard ecosystem. The results of this experiment point to the need to measure response variables other than rates of biological control to evaluate the effects of conservation biological control experiments. Suppression of pest damage can be achieved through other mechanisms rather than direct predator-prey or parasitoid host interactions. The ecosystem service of pest regulation can be achieved indirectly through subtle changes in ecosystem processes, e.g., host quality, competitive interactions, etc.