Efficiency of an attract-and-kill system with entomopathogenic nematodes against wireworms (Coleoptera: Elateridae)

Abstract: Wireworms (Coleoptera: Elateridae) are polyphagous soil-dwelling pests. This study aimed at contributing to the development of an attract-and-kill strategy combining plant natural extracts with entomopathogenic nematodes (EPNs). We first compared the efficiency of two EPN strains through classical screening laboratory assays (contact application of EPNs) and found 8.3 and 16.7% of mortality after 10 days for Steinernema carpocapsae B14 and Heterorhabditis bacteriophora, respectively. Then, we encapsulated EPNs with potato extracts (acting as attractant and feeding stimulant) in alginate beads and the results showed higher mortality rates: 16.7% and 41.7% for S. carpocapsae and H. bacteriophora, respectively. In absence of attractants in the beads, the mortality dropped to 0% (S. carpocapsae) and 8.3% (H. bacteriophora). We conclude that the ingestion of EPN lead to increased mortality, compared to contact application of EPNs. The association of volatiles organic compounds as attractants and EPNs as biological agents represent a promising alternative to pesticides that remains to be evaluated in the field.