Fungal Entomopathogens for pest biocontrol in multitrophic approaches

Beneficial micro-organisms associated to plants either as root colonizers or endophyte, known as hypocrealean entomopathogenic fungi (HEF), constitute new opportunities for managing crop pests and diseases. Plants, insects and aboveground trophic interactions play a key role in shaping the relationships between these players. Whereas the role of HEF in underpinning these interactions has recently been reported, there is little information about (1) HEF-mediate pest resistance in the plant, (2) their direct and indirect actions against insect pests of different orders, (3) their effect on aphid-borne diseases, and (4) on higher trophic level occurring between pests and their entomophagous beneficials. Here, we provide several recent results from different research projects performed on different insect models. Some HEF of the genus Metarhizium and Beauveria isolated from agricultural field in Belgium and Democratic Republic of Congo have been tested against sap-sucking insects such Myzus persicae, Macrosiphum euphorbiae, Sitobion avenae aphids and Halyomorpha halys bug but also chewing insect pest, namely Spodoptera frugiperda. Beside the evaluation of the direct effect of the tested fungal isolates on these insect pests, the endophytic actions of these treatments have been also assessed in different host plants namely sugar beet, tomatoes, wheat, faba bean, and maize. Moreover, the effect of these fungal treatments on beneficial insect, Episyrphus balteatus have been also evaluated. New sustainable and complementary strategies are proposed to cope with important insect pests based on the potentialities of entomopathogenic fungal strains as bio-insecticides displaying direct and indirect effects through host plants.