Effects of an entomopathogenic nematode applied against Thaumetopoea processionea on non-target arthropods under field conditions

Abstract

Entomopathogenic nematodes are increasingly used in biological pest control, and are considered to be environmentally friendly. However, due to their potentially wide range of insect hosts, they may detrimentally affect biodiversity. We here investigate effects of nematode applications against the oak processionary moth, Thaumetopoea processionea, on non-target organisms using beat sheet sampling and light trapping. While such effects have been repeatedly explored for soil and xylobiontic arthropods, effects on herbivorous insects are largely unexplored. We found no statistically significant short- or longer-term effects on either Lepidoptera or other insect orders. While we cannot completely rule out some weak short-term reductions in individual numbers (−12 %), considerable long-term effects on non-target insects can be largely ruled out. Provided a targeted localized application, applying the nematode Steinernema feltiae seems to be an environmentally friendly method for controlling populations of T. processionea at locations with increased risks for human health.