The lure of hidden death: development of an attract-and-kill strategy against Agriotes obscurus (Coleoptera: Elateridae) combining semiochemicals and entomopathogenic nematodes

Diana La Forgia,Ted Turlings,Raquel Campos-Herrera,Pamela Bruno,François Verheggen

doi:10.3906/zoo-2106-38

Abstract

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.

Highlights

Wireworms (Coleoptera: Elateridae) are common polyphagous soil-dwelling pests that are responsible for important economic losses (Jansson and Seal, 1994)
Attract-and-kill experiment The use of alginate beads with encapsulated nematodes affected the feeding behaviour of wireworms (χ2 = 56.77, p < 0.001)
The addition of potato extract increased the effects observed with S. feltiae AM25 population (Tukey: z = 3.91; p < 0.001), but did not impact those observed with S. carpocapsae e-nema

Summary

Introduction

Wireworms (Coleoptera: Elateridae) are common polyphagous soil-dwelling pests that are responsible for important economic losses (Jansson and Seal, 1994). They feed on roots and tubers of cereals, potatoes, sugarcane, and some ornamental plants (Parker and Howard, 2001). Neonicotinoids coated on seeds were effective in controlling wireworms; they are mostly banned from the European market. Several alternatives to pesticides have been proposed to control wireworms’ damage, including agricultural practices, microorganisms and semiochemicals (Traugott et al, 2015; Barsics et al, 2017; la Forgia and Verheggen, 2019)

Methods

Results

Discussion

Conclusion