The combination of the entomopathogenic fungus Metarhizium anisopliae with the insecticide Imidacloprid increases virulence against the dengue vector Aedes aegypti (Diptera: Culicidae)

Abstract

BackgroundDengue fever transmitted by the mosquito Aedes aegypti, is one of the most rapidly spreading insect borne diseases, stimulating the search for alternatives to current control measures. The dengue vector A. aegypti has received less attention than anophelene species, although more than 2.5 billion people are at risk of infection worldwide. Entomopathogenic fungi are emerging as potential candidates for the control of mosquitoes. Here we continue our studies on the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae against adult A. aegypti females. With the aim of further reducing mean survival times of A. aegypti exposed to fungus impregnated surfaces, a sub-lethal concentration of the neonicotinoid insecticide Imidacloprid (IMI) was added to fungal suspensions.ResultsA sub-lethal concentration of IMI that did not significantly alter the daily survival rates or mean survival percentages of mosquitoes was identified to be 0.1 ppm. This sub-lethal concentration was combined with M. anisopliae conidia (1 × 109 conidia mL-1). Both the combined treatment and the conidia alone were able to reduce the survival of A. aegypti compared with untreated or IMI treated mosquitoes. Importantly, mosquito survival following exposure to the combined treatment for 6 and 12 hrs was significantly reduced when compared with mosquitoes exposed to conidia alone.ConclusionsThis is the first time that a combination of an insecticide and an entomopathogenic fungus has been tested against A. aegypti. Firstly, the study showed the potential of IMI as an alternative to the currently employed pyrethroid adulticides. Secondly, as an alternative to applications of high concentrations of chemical insecticides, we suggest that adult A. aegypti could be controlled by surface application of entomopathogenic fungi and that the efficiency of these fungi could be increased by combining the fungi with ultra-low concentrations of insecticides, resulting in higher mortality following relatively short exposure times.

Isolation and efficacy of entomopathogenic fungus (Metarhizium anisopliae) for the control of Aedes albopictus Skuse larvae: suspected dengue vector in Pakistan

“…These dead mosquito larvae were placed in the Saboraud dextrose agar (SDA) plates supplemented with chloramphenicol (25 毺g/mL) as a bacteriostatic agent according to the method of Paula et al with some modification [13] . Incubator was used for incubation of these plates with larvae for 5 days, which was maintained at (24暲2 曟 ).…”

Characteristics and Virulence Assay of Entomopathogenic Fungus Nomuraea rileyi for the Microbial Control of Spodoptera exigua (Lepidoptera: Noctuidae)

“…2). 290 Lee et al Nomuraea rileyi는 30종이 넘는 나비목 유충에 대한 병원성을 보이며 밤나방과(Noctuidae)에 속하는 유충들에 감염을 잘 일으 켜 난방제 나비목 해충 방제를 위해서 많은 연구가 이루어 지고 있다 (Ignoffo, 1981;Ignoffo and Boucias, 1992;Sanchez-Peña, 2000;Martins et al, 2005). (Jaramillo et al, 2005;Santos et al, 2007;Brito et al, 2008;Paula et al, 2011;Sun et al, 2012). 또한 다른 친환경 방제제인 여러 가지 친환경 추출물 또는 천적 곤충과 곰팡이 살충제를 함 께 처리함으로써 곰팡이 살충제의 낮은 살충력을 보완 하면서 동시에 두 가지 모두 살충효과를 높일 수 있는 것에 대해 많은 연 구가 활발히 이루어지고 있다 (Wekesa et al, 2007;Rashki et al, 2009;Park and Kim, 2012).…”

Biological Control of Dengue Vectors

“…Studies have showed that A. aegypti had significantly increased mortality after exposure to M. anisopliae (Scholte, et al 2007;de Paula, et al 2008 and B. bassiana (de Paula, et al 2008. Worryingly, susceptibility to fungal infection is significantly reduced following a blood meal, but after digestion fungal susceptibility returned to pre-feeding levels (de Paula, et al 2011a). Also wild strains may be less susceptible to fungal infection than some colony strains used (de Paula, et al 2011b).…”