The lure of hidden death: Development of an attract-and-kill strategy againsagriotes obscurus (coleoptera: Elateridae) combining semiochemicals and entomopathogenic nematodes

Wireworms are polyphagous soil-dwelling pests that are hard to control. Attract-and-kill strategies, combining attractive semiochemicals with biocontrol agents, have great promise to control insect pests. We hypothesized that the combination of plant semiochemicals and entomopathogenic nematodes (EPNs) in an attract-and-kill system could greatly enhance the nematodes’ efficiency against wireworms. We evaluated the potential of alginate beads loaded with plant extracts and EPNs to control Agriotes obscurus. We tested the efficiency to kill wireworms or to reduce their feeding activity when combining potato tuber extracts as attractants with any of seven different EPN populations. While a direct application of EPNs on wireworms did not reduce the feeding activity nor increased their mortality, the combination of attractants and EPNs encapsulated in alginate beads resulted in attraction and consumption of the EPNs and caused up to 50% wireworm mortality with the EPN species Steinernema carpocapsae. Beads with EPNs caused a significant reduction of the wireworms’ feeding activity. This study shows that wireworms feeding on EPN-containing beads have their feeding activity and survival negatively affected. Considering their long developmental time and the survival capability of EPNs in the soil, implementing this attract-and-kill system in the field might be a suitable strategy for the long-term management of wireworms.
The authors thank Ricardo Machado from the University of Bern (Switzerland), Selcuk Hazir from the Aydın Adnan Menderes University (Turkey) and Fernando García del Pino from the Universidad Autónoma de Barcelona (Spain) for providing the nematodes populations that were used in the experiments. The authors also thank to Mickaël Gaillard for the statistical help. The results presented in this study are part of the PhD thesis by the first author DLF, supported by a Ph.D. grant from Coordinated Integrated Pest Management in Europe (C-IPM), project ElatPro. RCH is awarded by Ramon y Cajal contract award (RYC-2016-19939) from the Government of Spain.