Susceptibility of larvae of wireworms (Agriotes spp.) (Coleoptera: Elateridae) to some Turkish isolates of entomopathogenic nematodes under laboratory and field conditions

Abstract

In the present study, the virulence of some local entomopathogenic nematode (EPN) isolates (S. carpocapsae E-76, S. feltiae KCS-4-S, H. bacteriophora FLH-4-H, S. bicornotum MGZ-4-S and H. indica 216-H) recovered from the surveys conducted in Adana, Kayseri, and Kahramanmaras provinces on the 5th or 6th larval instar of Agriotes spp. (Coleoptera: Elateridae) were investigated under laboratory and field conditions. Laboratory studies were carried out in 100 ml plastic containers including autoclaved soil at different temperatures (25 and 30 °C) and concentrations (25, 50 and 100 IJs/cm2). The infective juveniles of S. carpocapsae E-76 and H. indica 216-H isolates were applied at the concentration of 1x106 IJs/m2 with a back pack sprayer with a 0.5 mm nozzle in the field trial. In the laboratory studies, the mortality rates generally increased with the increasing temperatures, concentrations and exposure times. The highest mortality rate (65%) was achieved by two isolates (S. bicornotum MGZ-4-S and S. carpocapsae E-76) at the highest concentration (100 IJs/cm2) 21 days after inoculation at 25 °C. The most efficient isolate at 30 °C was S. bicornotum MGZ-4-S and caused 75% mortality 21 days after treatment. In the field study, S. carpocapsae E-76 performed better than H. indica 216-H isolate and caused 55% mortality on the larval instar of wireworms. The current study suggests that some of the EPN isolates tested have good potential for the biological control of wireworm. However, further studies are needed to enhance the effectiveness of EPN isolates.