Effects of codling moth control programs using spinetoram on woolly apple aphid biological control

Since the commercial introduction of Delegate (spinetoram) in 2008 for codling moth, Cydia pomonella (L.), control, outbreaks of the woolly apple aphid (WAA), Eriosoma lanigerum (Hausmann), have increased in Pennsylvania apple orchards. Intensive biodiversity samples taken from colored pan traps in commercial orchards from 2007-9 show reductions in woolly apple aphid biocontrol agents that correlate with higher WAA populations in orchards treated with spinetoram. In 2010, we used yellow sticky cards for weekly monitoring of the WAA parasitioid Aphelinus mali (Haledman) in commercial orchards for the first time. In paired plots from five commercial apple orchards, we found significantly lower populations of A. mali in orchards treated with spinetoram for first generation codling moth control than in plots where codling moth was treated with the insecticide Belt (flubendiamide). In these same plots, WAA populations reached higher levels and were more persistent in the Delegate plots than in the Belt treated plots.