Assessing effects of soil fungal bioinocula on aboveground arthropod pests and beneficials in strawberry (Fragaria × ananassa) fields

Strawberry plants are attacked by various arthropod herbivores, including insects and mites, causing damage to different parts of the plants during the season. Strawberry plantations also harbour beneficial arthropods such as predators, parasitoids and pollinators (e.g., predatory mites, lacewings, hoverflies,). Applications of beneficial fungi may enhance plant growth and decrease the incidence of specific arthropod pests, but their impact on entire arthropod communities is largely unknown. Two-season field trials were conducted in Denmark and Slovenia to study effects of the entomopathogenic Metarhizium brunneum, the mycoparasitic Clonostachys rosea, and arbuscular mycorrhizal biofertilizers, all fungi, on the main pest and beneficial arthropods in integrated (IPM) and organic (ORG) strawberry production systems. Soildeployed bioinocula had limited impact on aboveground arthropod assemblages, but treatment with the M. brunneum bioinoculum significantly increased the number of predators in the trials in Slovenia, while reducing arthropod abundance and diversity in Denmark. Agricultural management strongly affected arthropod communities, with ORG trials harbouring higher arthropod abundance and diversity compared to IPM, suggesting potential benefits of sustainable farming practices. The nuanced relationships among herbivores, beneficials, and pest infestations invites further investigation to unravel the underlying ecological mechanisms shaping pest dynamics in diverse agricultural landscapes.