Efficacy of Metarhizium anisopliae Isolates Against Soil-Dwelling Larvae of Agriotes spp. (Coleoptera: Elateridae)

Abstract

Soil-dwelling larvae of Agriotes spp. (Coleoptera: Elateridae), commonly known as wireworms, are destructive agricultural pests causing serious damage to roots, tubers, and underground plant tissues in various crops. The increasing limitations associated with chemical insecticides have encouraged the exploration of environmentally sustainable biological control agents. The present study evaluated the efficacy of different Metarhizium anisopliae isolates against soil-dwelling larvae of Agriotes spp. under laboratory and greenhouse conditions. Fungal isolates were cultured and applied at varying concentrations to assess their pathogenicity, larval mortality, and infection efficiency. Mortality rates, median lethal time, and mycosis development were recorded to compare the virulence of tested isolates. Results demonstrated significant differences in pathogenicity among M. anisopliae isolates, with certain strains inducing high larval mortality and rapid fungal colonization. Infected larvae exhibited typical symptoms including reduced mobility, body discoloration, and external fungal growth. Environmental factors such as soil moisture and temperature influenced fungal activity and infection success, with favorable conditions enhancing pathogen performance. Greenhouse experiments confirmed the potential of highly virulent isolates to suppress wireworm populations and reduce root damage in treated plants. The antagonistic action of M. anisopliae was associated with fungal penetration through the insect cuticle and subsequent internal colonization leading to host death. The findings highlight the potential application of selected M. anisopliae isolates as eco-friendly biological control agents against Agriotes larvae. This study contributes valuable information for the development of sustainable integrated pest management strategies aimed at reducing wireworm infestations and minimizing dependence on chemical insecticides in agricultural production systems.