Use of insect-pathogenic nematodes against Drosophila suzukii

Spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), originating from Asia and spreading in Europe since around 2008 has become a major pest of small and stone fruits as well as grapevines in Austria. Due to its enormous reproductive potential, control of this pest is difficult. So far, management is primarily achieved by application of insecticides. However, their application in the field is problematic due to the in many cases short period between infestation and harvest, legally required waiting times, potential residues and side effects on bees and beneficial organisms. Entomopathogenic nematodes have been used to successfully control a wide range of insect pests so far. Therefore, laboratory and field trials were conducted to determine whether nematodes of the species Heterorhabditis bacteriophora and Steinernema feltiae have the potential to interfere with fly development and thus to slow down population growth. In the laboratory experiments, both nematode species significantly reduced the number of hatched adult flies. In the field, adult eclosure was negatively affected by both nematode species, a statistically significant effect, however, was recorded for H. bacteriophora only. The work enlarges the understanding in respect to future management strategies.