Identification ofMetarhiziumstrains highly efficacious againstAedes,AnophelesandCulexlarvae

Abstract

Entomopathogenic fungi, such as Metarhizium anisopliae and Beauveria bassiana, have been shown to be efficacious in killing mosquito larvae of different mosquito species. The current study compared the pathogenicity and efficacy of two formulations of three fungal strains against different instars of three mosquito species with the aim of identifying the most virulent strain for use under field conditions. Three strains of Metarhizium, ARESF 4556, ARSEF 3297 and V275, were assayed against early (L 2−3 ) and late (L 3-4 ) instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Two formulations of the fungi were tested, dry conidia and aqueous suspensions (i.e. 'wet' conidia). Effects of all combinations of conidia, mosquito species, instar, fungal strain and concentration on mosquito mortality were analysed using Cox regression and Kaplan-Meier analyses. Strain ARSEF 4556 was more virulent than ARSEF 3297 and V275, with LT 50 values ranging from 0.3 to 1.1 days, with Anopheles and Culex being more susceptible than Aedes. Early and late instars were equally susceptible independent of species. Although the formulation did influence mortality rates, both 'wet' and 'dry' conidia applications were highly effective in killing mosquito larvae. Viable spores were more efficacious than heat killed spores. The latter did cause mortality but only at high concentrations. Metarhizium sp. has proved to be effective in reducing survivability of all larval stages of Aedes, Anopheles and Culex under laboratory conditions. Aedes larvae were generally more tolerant than Anopheles and Culex irrespective of fungal strain.

The microbiomes of a XVIII century mummy from the castle of Krásna Hôrka (Slovakia) and its surrounding environment

“…Some of these have previously been isolated from mummified human remains, for example Aspergillus and Talaromyces, which also exhibited biodegradative potential (Naji et al, 2014;Šimonovi cová et al, 2015). The occurrence of Metarhizium, an entomopathogenic fungus (Greenfield et al, 2015), is likely associated with the presence of the different insects that colonized the mummified body. The mycobiome included wood-degrading fungi, for example members of the genera Hypholoma, Xylobolus, Strobilurus and Trametes (Sánchez, 2009;Zmitrovich et al, 2014).…”

Significant mortality of eggs and young larvae of two pine processionary moth species due to the entomopathogenic fungus Metarhizium brunneum

“…This study shows that the eggs and newly emerged larvae of both species of pine processionary moth T. pityocampa and T. wilkinsoni, are highly susceptible to M. brunneum ARSEF4556 and V275, as it caused 100% mortality within a relatively short time of 7-10 days. Both ARSEF4556 and V275 have also been shown to be highly virulent strains for other pest species including thrips (Ansari et al, 2007), midges (Ansari et al, 2010) and mosquitoes (Greenfield et al, 2015). The pine processionary moth larvae appear to be naturally susceptible to entomopathogens (Vargas-Osuna et al 1994;Er et al, 2007;Sevim et al, 2010;Draganova et al, 2013) with B. bassiana often reported as infecting larvae and pupae with variable results (Battisti et al, 2000;Sevim et al, 2010).…”

Highly specific host-pathogen interactions influence Metarhizium brunneum blastospore virulence against Culex quinquefasciatus larvae

“…Different fungal isolates can exhibit considerable variation in their virulence levels and host ranges [2,3]. Some Metarhizium species (e.g.…”