Biological control of Drosophila suzukii (Diptera: Drosophilidae) using entomopathogenic nematodes

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a vinegar fruit fly that has invaded the Americas, Europe and Africa. It is a major insect pest of soft fruit including small fruit and stone fruit. This pest has caused significant damage to the Florida blueberry industry. Currently, chemical insecticides are the primary method of control for D. suzukii. It is important that we find alternatives methods of controlling this pest, such as, biological control agents. Entomopathogenic nematodes (EPN) are commercially available biological control agents that are widely used against soil-dwelling life stages of pests. We investigated the susceptibility of D. suzukii larvae to four commercially available EPN species. There were five treatments consisting of: Steinernema riobrave, S. Carpocapsae, S. feltiae, and Heterorhabditis bacteriophora, and a control of distilled water. Each treatment was replicated ten times. Each plot consisted of a Petri dish lined with one sheet of filter paper. Nematodes were applied at a concentration of 150IJs/cm^-2. After inoculation, ten D. suzukii larvae were placed in the petri dish, which were then sealed and stored in an environmental chamber (Model 136VL, Percival Scientific, Inc. Perry, IA) set at 24°C with a 12:12 h light:dark cycle. Treatments were inspected every 24 hours to assess for infection until D. suzukii emerged. All species were able to infect D. suzukii larvae. Steinernema feltiae and S. carpocapsae achieved the greater efficacy (92% and 85%, respectively). Our results show the potential of EPNs as biological control agents against D. suzukii.