Isolation of Entomopathogenic Bacteria From Larvae of a Lepidopteran Specie; Galleria Mellonella and Study of Their Insecticidal Effect

Abstract

SUMMARYFew years ago, considerable progress has been made to explain the disappearance of bee colonies, including correct identification of pests involved and the search for more effective and healthy alternatives to protect them. Indeed, our work is based on the isolation, characterization and identification of entomopathogenic bacterial strains of the genus Bacillus from larvae of wax moth Galleria mellonela reared in the laboratory, with a preliminary study of the use of these entomopathogenic bacteria on the larvae (L5) of G. mellonella under controlled conditions. In fact, 9 bacterial strains of the genus Bacillus have been isolated. They are spore forming bacteria, Gram, catalase and oxidase positive and present variable responses to the gelatinase test, lecitinase, caseinase, culture in anaerobiosis and growth at different temperatures (45 ° C., 55 ° C., 65 ° C.). From our study, we also find that the strain S4, probably identified as Bacillus thuringiensis, has a better effect on the larvae of Galleria mellonella. It caused very remarkable symptoms and mortality rates that vary depending on the strain and bacterial concentration tested and the mode of application. Injection of strain S4 for individuals resulted mortality of 83.33%, 75% and 50%, respectively, after treatment with high, medium and low concentration after only 3 days. The comparative examination of the hemolymph test results shows that the injection of the bacteria into the larvae resulted in a significant increase in hemolymph protein and carbohydrate content as compared to controls.

Biological Control of Honey Bee Diseases and Pests

“…In addition, other entomopathogenic microorganisms (fungi, nematodes, etc.) have been tried on the wax moth, but no results have been obtained as an effective agent [49][50][51][52][53].…”

Phylogeny and Molecular Study of Some Entomopathogenic Rhizobacteria Isolated from Two Regions in Algeria

“…Among the key insect-pest in Algeria, Locusta migratoria (Orthoptera-Acrdidae) and Galleria mellonela (Lepidoptera-Pyralidae) exhibit different damage to agriculture and are distributed in all the country (Oulebsir-Mohandkaci et al, 2016;Benzina et al, 2017). With increased awareness towards the environment, biological methods to control these two pests such as biopesticides based on entomopathogenic have been receiving greater attention as alternatives to chemicals pesticides (Jaronski, 2010).…”

“…To facilitate the isolation of entomopathogenic strains from soil, insect baiting by Galleria mellonella or the 'Galleria-bait method' (Zimmermann 1986;Benzina et al, 2017), is the most renowned methodology. The migratory locust was also used for this.…”