Impact of entomopathogenic fungi on soil non-target species

The ban on chemical pesticides for insect pest control has intensified the search for alternative strategies, including the use of biocidal microorganisms such as entomopathogenic fungi (EPF). These agents are promising tools for sustainable pest management, yet their ecological safety, particularly sublethal effects on non-target organisms, remains an area requiring deeper exploration. This study assessed the safety of a new EPF formulation targeting wireworms, a major soil-dwelling pest, by evaluating lethal and sublethal impacts on three non-target species: the common black ant (Lasius niger), the ground beetle (Pterostichus melanarius), and the earthworm (Eisenia fetida). After exposing ant colonies for one-hour or 24-hour to the formulation, we found no impact on ants’ survival and foraging behavior. Ground beetles’ survival was monitored over 21 days of continuous exposure and, although no significant mortality was observed, a behavioral assay revealed an increased biting frequency in the presence of EPF formulation, possibly indicative of altered stress or foraging responses. E. fetida, survival was evaluated over 28 days, and morbidity and behavior were assessed after exposure. While EPF did not impact survival, locomotor activity, or reproductive capacity, earthworms exhibited reduced weight gain and increased foraging behavior. These findings demonstrate that while the EPF formulation targeting wireworms does not exhibit biocidal effects on these non-target species, subtle behavioral and physiological changes may occur, potentially impacting ecosystem functions such as predation, decomposition, and soil health. This study highlights a persistent gap in understanding their ecological implications and calls for the integration of these endpoints into routine risk assessment protocols for biocontrol agents.