Potential of moroccan entomopathogenic nematodes in controlling polyphagous fruit flies, Drosophila melanogaster (Meigen, 1830) and D. simulans (Sturtevant, 1919), under variable abiotic conditions in strawberry agroecosystems

Abstract

Drosophila species, specifically Drosophila melanogaster (Meigen, 1830) and Drosophila simulans (Sturtevant , 1919), are one of the most economically damaging pests in red berry production systems, particularly strawberry crops. Insect pests have traditionally been controlled through the application of chemical insecticides, which can severely damage the environment and pose serious risks to human health. An environmentally friendly alternative for controlling and managing pests is biological control using entomopathogenic nematodes (EPNs) as a possible biological control agent. This study evaluated the virulence of four indigenous Moroccan EPN strains, Steinernema feltiae (SF-MOR9, SF-MOR10) and Heterorhabditis bacteriophora (HB-MOR1, HB-MOR2) under controlled laboratory and greenhouse conditions against third instar larvae of D. melanogaster and D. simulans . Bioassays examined the effects of abiotic factors: two temperatures (25 °C and 28 °C), three photoperiods (light, obscurity, and 12:12 h L/O), three doses of EPNs (25, 50, 100 IJs cm - ²), and two substrate sources (soil and fruit). Nematode efficacy varied significantly with temperature, photoperiod, species, and dose. H. bacteriophora strains, particularly HB-MOR2, achieved consistent mortality rates exceeding 97 % under optimal conditions. These findings highlight the potential of indigenous Moroccan EPNs, especially H. bacteriophora, as sustainable biological control agents for integrated pest management (IPM) of Drosophila species in strawberry agroecosystems