European earwig, Forficula auricularia, distribution and susceptibility to biological control agents in midwest tree fruit production

The European earwig, (Forficula auricularia: Linnaeus) is an epigeal arthropod with multiple roles in orchard ecosystems including that of detritivore, predator of aphid, scale, and lepidopteran pests, and an infrequent pest. Previous research in Washington apple orchards demonstrated that that lower populations of earwigs were present in orchard blocks managed with broad-spectrum insecticides when compared to orchard blocks managed with softer, reduced-risk insecticides. Due to consumer safety, non-target, and ecosystem service concerns, broad spectrum insecticides are largely being phased out of tree fruit production, while acreage devoted to organic tree fruit production is increasing to meet consumer demands. Little information is currently available about the European earwig in Midwest tree fruit prodcution, thus the goal of this research was to expand the knowledge of the fate of the European earwig in such production systems. More explicitly, the objective of this resesarch was twofold: first, to determine the impact of conventional and organic tree fruit management programs on European earwig populations, and second to ascertain the susceptibility of the European earwig to two microbial control agents used in organic tree fruit pest managment programs. Earwigs were monitored using simple corrugated cardboard traps at three intervals through out the 2011-2012 growing seasons. Field collected earwigs were exposed to the microbial control agents Steinernema riobrave and Beauveria bassiana in laboratory assays to determine the median lethal dose.