The use of entomopathogenic nematodes in the management of wireworms (Agriotes spp.) (Coleoptera: Elateridae) in potato

Wireworms (Agriotes spp.) (Coleoptera: Elateridae) cause significant economic crop losses in potato cultivation. In this study, surveys were conducted for the first time to determine the presence of entomopathogen nematodes (EPN) and wireworms in 7 provinces where potatoes are grown in our country in 2020-2021. As a result of morphological/morphometric and molecular analysis of 48 EPN isolates, 34 were identified as Steinernema feltiae, 13 as Heterorhabditis bacteriophora and 1 as Oscheius tipulae. Of the 54 wireworms, 48 were identified as Agriotes sputator and 6 as Agriotes rufipalpis as a result of molecular analysis. To investigate the effectiveness of EPNs under laboratory conditions, 6 EPNs isolates were randomly selected. The effectiveness of these isolates against A. sputator and A. rufipalpis species was evaluated by looking at the mortality rates at 5 different infective juvenile (IJ) doses at 25 and 30oC the 3rd and 7th day of the trial. The highest mortality rate on day 3 was in A. sputator larvae, with 50% in Sf_BL22 and Hb_AF12 isolates. On day 7, the highest mortality rates was 87.5% Sf_BL24 by A. sputator and by Hb_AF12 on A. rufipalpis, respectively. At the highest application dose, all isolates generally showed a biological activity of over 80%. In pot trials, the highest mortality rate on day 3 was 40% of A. rufipalpis larvae created by Sf_KAY4 isolate and the highest mortality rate on day 7 was 67.5% of A. sputator larvae created by Sf_BL22 isolate. The two most effective EPN isolates (Sf_BL22 and Hb_N3) and their doses (1,000,000-1,500,000 IJ/m2) and an insecticides with the active ingredient imidacloprid were applied in research plots, Bolu and Afyonkarahisar provinces. In these provinces, reductions of 62-90% were observed for both wireworm species populations in EPN application plots. It was determined that this decrease was close to that of insecticide application.