Nontarget effects of orchard pesticides on natural enemies: Lessons from the field and laboratory

Publication date: Available online 22 April 2016 Source:Biological Control Author(s): Elizabeth H. Beers, Nicholas J. Mills, Peter W. Shearer, David R. Horton, Eugene R. Milickzy, Kaushalya G. Amarasekare, Lessando M. Gontijo The nontarget effects of insecticide programs used to control codling moth, Cydia pomonella Linnaeus (Lepidoptera: Tortricidae), were studied in large-plot field trials in apples, pears, and walnuts in the western United States. We assessed the health of the natural enemy community by sampling the abundance of natural enemies and by monitoring for outbreaks of secondary pests. The insecticides used in the field tests overlapped those tested in laboratory bioassays. Using these parallel lab and field studies, we examined two hypotheses: 1) pesticides found to have negative effects on natural enemy fitness in laboratory bioassays will predict reductions in natural enemy densities in the field, and 2) reductions in natural enemy densities in the field will result in outbreaks of secondary pests. We found only one clear instance, Forficula auricularia (Linnaeus) (Dermaptera: Forficulidae), where laboratory results documenting negative effects corresponded to a significant reduction in field studies (apple). This same instance was the only case where a reduction in a natural enemy population was associated with a significantly increased density of a secondary pest, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae). There were several inst...
Source: Biological Control - Category: Biology Source Type: research