Effectiveness of Steinernema rarum PAM 25 (Rhabditida: Steinernematidae) Against Drosophila suzukii (Diptera: Drosophilidae).

Drosophila suzukii (Matsumura 1931) represents one of the main pests of small fruits. The use of biological agents is very promising for insect control. In the present study, the nematode Steinernema rarum PAM 25 was evaluated for the control of D. suzukii pupae, this species has not been evaluated previously. First, we evaluated the pathogenicity of S. rarum PAM 25 at the concentration of 1,000 infective juveniles (IJs) inoculated into D. suzukii pupae. In the second bioassay, we evaluated the influence of 1,500; 2,000; 2,500; 3,000; 4,000 IJs/ml nematode concentration and temperature on D. suzukii mortality. In the third bioassay, we evaluated the influence of the isolate S. rarum PAM 25 on D. suzukii adult lifespan following pupal infection, using the concentrations with the highest mortality rate of pupae at each temperature as determined in the second experiment. The S. rarum PAM 25 isolate is pathogenic to D. suzukii. The most effective temperature for S. rarum PAM 25 activity was 14°C at a concentration of 4,000 IJs/ml. Adults infected with S. rarum PAM 25 showed a significant reduction in longevity. The results confirmed the potential of S. rarum PAM 25 for the control of D. suzukii.