Efficacy of the entomopathogenic nematode, Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) on Mecorhis ungarica (Herbst, 1784) (Coleoptera: Rhynchitidae)

Abstract

Background: In this study, the virulances of 4 different concentrations of the entomopathogenic nematode, Steinernema feltiae (Filipjev) on adults of the rose weevil, Mecorhis ungarica (Herbst, 1784) (Coleoptera: Rhynchitidae) were tested under laboratory conditions. Results: Ten replications for each concentration where 5 adults for each replicate were used. Suspensions prepared from each concentration, containing 3rd instar juveniles (infective juveniles) of S. feltiae, were sprayed on the pest adults for 20 s at 1 atm pressure. Deltamethrin was applied, at the recommended concentration (30 ml/ha), as a positive control, while pure water was used as negative control. Observations started 72 h after the applications and continued until the 15th day. The White Trap Method used for the re-isolation of nematodes from dead individuals obtained in observation days. As a result of the study, obtained mortality rates in concentration of S. feltiae (100, 150, 200, 250 million IJs/100 l water) were not different from each other but were found significant than control (P < 0.05). Additionally, among the number of re-isolated 3rd juveniles, the highest mean number was found on 200 million IJs concentration and the lowest mean was determined on 150 million IJs concentration. Tested concentrations of S. feltiae caused 80, 86, 82, and 92% death on adult individuals on the 15th day. Mortality rates caused by each concentration depending on the time were not significant between each other (P > 0.05). Conclusion: In this study, it was determined that different concentrations of S. feltiae were effective on adults of rose weevil. It is thought that entomopathogenic nematodes may be an alternative and promising biological control strategy to reduce the risk of pesticide residues in oil-bearing rose production areas.