Insecticidal potential of Brevibacillus laterosporus against dipteran pest species in a wide ecological range

Abstract

In order to increase our understanding of the insecticidal potential of the entomopathogenic bacterium Brevibacillus laterosporus strain UNISS 18 against insect pests, investigations were conducted on a selection of dipteran species including fruit flies, house flies, blow flies, and mosquitoes, characterized by adaptations to very diverse habitats. According to lethal concentration (LC₅₀) values, the common house mosquito Culex pipiens (LC₅₀ = 0.10 × 10⁶ spores/mL) and the yellow fever mosquito Aedes aegypti (LC₅₀ = 0.18 × 10⁶ spores/mL) were significantly more susceptible than the flies. The blow flies were the second taxon in term of susceptibility to B. laterosporus spores, with a higher mortality in Calliphora vomitoria (LC₅₀ = 78.84 × 10⁶ spores/mL) than Lucilia caesar (LC₅₀ = 148.30 × 10⁶ spores/mL). The effectiveness of B. laterosporus spores was reduced by half in the house fly Musca domestica (LC₅₀ = 82.41 × 10⁶ spores/mL). The lowest susceptibility was observed in the fruit flies, among which the spotted wing drosophila (SWD), Drosophila suzukii, was the most susceptible (LC₅₀ = 217.51 × 10⁶ spores/mL) in comparison with the medfly Ceratitis capitata and the olive fly Bactrocera oleae (LC₅₀ = 2567.32 and 2567.36 × 10⁶ spores/mL, respectively). The present study demonstrated that significantly different degrees of susceptibility are associated with diverse dipteran species including plant and animal parasites, and we suggest that B. laterosporus established different relationships with dipteran species in different ecosystems.

Keywords: Bacteria; Bioinsecticide; Flies; Mosquitoes; Pest management.