Isolation of fungi from dead arthropods and identification of a new mosquito natural pathogen

Abstract

BackgroundInsects are well known vectors of human and animal pathogens and millions of people are killed by mosquito-borne diseases every year. The use of insecticides to target insect vectors has been hampered by the issues of toxicity to the environment and by the selection of resistant insects. Therefore, biocontrol strategies based on naturally occurring microbial pathogens emerged as a promising control alternative. The entomopathogenic fungus Beauveria bassiana is well characterized and have been approved by the United States Environmental Protection Agency as a pest biological control method. However, thousands of other fungi are unexploited and it is important to identify and use different fungi for biocontrol with possibly some vector specific strains. The aim of this study was to identify new fungal entomopathogens that may be used as potential mosquito biocontrol agents.MethodsCadavers of arthropods were collected from pesticide free areas and the fungi associated isolated, cultured and identified. Then the ability of each isolate to kill laboratory insects was assayed and compared to that of B. bassiana.ResultsIn total we have isolated and identified 42 fungal strains from 17 different arthropod cadavers. Twenty four fungal isolates were cultivated in the laboratory and were able to induce sporulation. When fungal spores were microinjected into Drosophila melanogaster, eight isolates proved to be highly pathogenic while the remaining strains showed moderate or no pathogenicity. Then a selection of isolates was tested against Aedes mosquitoes in a model mimicking natural infections. Only one fungus (Aspergillus nomius) was as pathogenic as B. bassiana and able to kill 100 % of the mosquitoes.ConclusionThe obtained results are encouraging and demonstrate the feasibility of this simple approach for the identification of new potential mosquito killers. Indeed, it is essential to anticipate and prepare biocontrol methods to fight the expansion of mosquitoes’ habitat predicted in certain geographical areas in association with the occurring climatic changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1763-3) contains supplementary material, which is available to authorized users.

Evaluation of genotoxic and cytotoxic effects of ethyl acetate extract of Aspergillus flavus on Spodoptera litura

“…(Jaber et al . ). In the present study, phytochemical screening of extract found the presence of phenolics.…”

“…The finding is in agreement with previous findings which highlighted the insecticidal potential of Aspergillus nominus isolated from dead arthropod against Aedes sp. (Jaber et al 2016). In the present study, phytochemical screening of extract found the presence of phenolics.…”

Isolation and identification of Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes and their larvicidal activity against Aedes aegypti

“…In addition, the continued use of chemicals over a long period of time can induce insecticide resistance in mosquito populations. The biological control agents used against Aedes mosquitoes include Bacillus thuringiensis israelensis or B. sphericus and their toxins and Xenorhabdus / Photorhabdus [ 15 – 19 ], fungi Metarhizium anisopliae and Beauveria bassiana [ 20 – 22 ], the protozoan Acanthamoeba polyphaga [ 23 ] and the copepod Macrocyclops albidus [ 24 ]. It has been suggested that Bacillus thuringiensis , Xenorhabdus and Photorhabdus have potential for the biological control of Aedes mosquitoes.…”

Compatibility of insecticides with Metarhizium brunneum (Petch) and Beauveria bassiana(Bals.) for bio-intensive management of pink mealybug, Maconellicoccus hirsutus (Green)in grapes

“…Combined gene sequence of EF (EF-1α exon + 5'EF-1α intron region), beta-tubulin and RPB2 sequences of M. brunneum were submitted to GenBank-NCBI with accession numbers MH711929, MH711930 and MH711931, respectively. Beauveria bassiana was isolated from field infected mealy bug in vineyards as per the procedure described by Jaber et al (2016) and stored on Potato Dextrose Agar (PDA) slants at 4°C, until further use.…”