Neem oil increases the efficiency of the entomopathogenic fungus Metarhizium anisopliae for the control of Aedes aegypti (Diptera: Culicidae) larvae

Abstract

BackgroundEntomopathogenic fungi are potential candidates for use in integrated vector management and many isolates are compatible with synthetic and natural insecticides. Neem oil was tested separately and in combination with the entomopathogenic fungus Metarhizium anisopliae against larvae of the dengue vector Aedes aegypti. Our aim was to increase the effectiveness of the fungus for the control of larval mosquito populations.MethodsCommercially available neem oil was used at concentrations ranging from 0.0001 to 1 %. Larval survival rates were monitored over a 7 day period following exposure to neem. The virulence of the fungus M. anisopliae was confirmed using five conidial concentrations (1 × 105 to 1 × 109 conidia mL−1) and survival monitored over 7 days. Two concentrations of fungal conidia were then tested together with neem (0.001 %). Survival curve comparisons were carried out using the Log-rank test and end-point survival rates were compared using one-way ANOVA.Results1 % neem was toxic to A. aegypti larvae reducing survival to 18 % with S50 of 2 days. Neem had no effect on conidial germination or fungal vegetative growth in vitro. Larval survival rates were reduced to 24 % (S50 = 3 days) when using 1 × 109 conidia mL−1. Using 1 × 108 conidia mL−1, 30 % survival (S50 = 3 days) was observed. We tested a “sub-lethal” neem concentration (0.001 %) together with these concentrations of conidia. For combinations of neem + fungus, the survival rates were significantly lower than the survival rates seen for fungus alone or for neem alone. Using a combination of 1 × 107 conidia mL−1 + neem (0.001 %), the survival rates were 36 %, whereas exposure to the fungus alone resulted in 74 % survival and exposure to neem alone resulted in 78 % survival. When using 1 × 108 conidia mL−1, the survival curves were modified, with a combination of the fungus + neem resulting in 12 % survival, whilst the fungus alone at this concentration also significantly reduced survival rates (28 %).ConclusionsThe use of adjuvants is an important strategy for maintaining/increasing fungal virulence and/or shelf-life. The addition of neem to conidial suspensions improved virulence, significantly reducing larval survival times and percentages.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1280-9) contains supplementary material, which is available to authorized users.

Eradication of Mosquito Borne Diseases by Entomopathogenic Fungi

“…Metarhizium [11,[14][15][16][17][18][19] and Beauveria bassiana [15,20] at varying concentrations to check effect as a larvicide.…”

Fungos: Biodiversidade E Biotecnologia, Um Breve Panorama

“…Já o processo de infecção e colonização, ocorrem em tempos distintos, pois são dependentes do hospedeiro em questão (KORDI et al, 2015;KIM et al, 2013;KIM et al, 2010). Aedes aegypti, transmissor de diversas doenças que causam preocupações na saúde pública (GOMES et al, 2015;PEREIRA et al, 2009). ABSTRACT: An endophytic fungi is the one that lives totally or partially inside the plants, generally inhabiting its aerial parts without apparently causing damage to its hosts, living in symbiosis with the plant.…”

IDENTIFICAÇÃO POLIFÁSICA DE ISOLADOS CLÍNICOS DO COMPLEXO Candida Parapsilosis

“…No parâmetro comercial brasileiro, produtos contendo M. anisopliae como princípio ativo, são os mais registrados no Ministério da Agricultura, Abastecimento e Pecuária (MAPA). Estudos com este entomopatógeno se intensificaram no país, principalmente com a possibilidade da sua utilização como controlador das larvas do Aedes aegypti, transmissor de diversas doenças que causam preocupações na saúde pública (GOMES et al, 2015;PEREIRA et al, 2009). to analyze the enzymatic activity of protease produced by endophytic fungi isolated from Avelós (Euphorbia tirucalli L.).…”