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.

Os conteúdos deste periódico de acesso aberto estão licenciados sob os termos da Licença Creative Commons Atribuição-UsoNãoComercial-ObrasDerivadasProibidas 3.0 Unported. Civitas Porto Alegre v. 14 n. 1 p. 66-80 jan.-abr. 2014 Dossiê: Diálogos do Sul Por uma razão decolonial Desafios ético-político-epistemológicos à cosmovisão moderna Towards a decolonial rationality Ethical-political-epistemological challenges to the modern worldview Adelia Miglievich-Ribeiro* Resumo: A revisão das epistemologias modernas impõe-se como desafio teórico para a inteligibilidade do mundo em sua hibridez; também como desafio ético e político, na medida em que explicita a exclusão e o silenciamento de sujeitos levados à desumanização, tendo seus saberes e cosmovisões negados como explicativos e orientadores legítimos de condutas. Combino neste texto a reflexão de Boaventura de Sousa Santos acerca do "paradigma prudente para uma vida decente" com as teses da "modernidade-colonialidade-decolonialidade" latino-americana. Associando a hermenêutica diatópica de Santos e a hermenêutica pluritópica de Mignolo, acentuo a urgência do diálogo a partir do Sul entre as distintas esferas culturais bem como da ação descolonizadora das subalternidades mediante a ênfase nas experiências singulares, na tradução e na articulação das diferenças em torno de projetos plurais de reconhecimento de sujeitos e suas vozes para a ampliação do universal como diversalidade.

A new system for deployment of fungus-impregnated black cloths was tested against and 48 hr to a PET trap with adhesive film + black cloth resulted in higher rates of trapped mosquitoes (38.6% and 68%, respectively) when compared with adhesive film only (6% and 12.6%, respectively). Both fungal species were effective at reducing survival rates when mosquitoes were exposed to traps for 24 hr or 48 hr. Lower exposure times did not significantly alter survival rates when compared to controls. The results showed that five traps or three traps per room were equally effective in reducing mosquito survival rates when testing both fungal species. The results for sucrose-fed insects showed significant reductions in survival when exposed to M. ansiopliae or B. bassiana for 24, 48 or 120 hr when compared to control survival, with the lowest survival rates seen following 48-or 120-hr exposures. Survival of blood-fed mosquitoes exposed to fungus-impregnated traps for 48 hr was not significantly different to the controls; however, longer exposure times significantly reduced survival rates. PET traps could be an effective system for deploying fungus-impregnated cloths in residences, facilitating cooperation of volunteers and reducing distribution time. K E Y W O R D Sattraction, biological control, dengue, traps, vector, zika

Background The use of entomopathogenic fungi (EPF) for the control of adult mosquitoes is a promising alternative to synthetic insecticides. Previous studies have only evaluated conidiospores against adult mosquitoes. However, blastospores, which are highly virulent against mosquito larvae and pupae, could also be effective against adults. Methods Metarhizium anisopliae (ESALQ 818 and LEF 2000) blastospores and conidia were first tested against adult Aedes aegypti by spraying insects with spore suspensions. Blastospores were then tested using an indirect contact bioassay, exposing mosquitoes to fungus-impregnated cloths. Virulence when using blastospores suspended in 20% sunflower oil was also investigated. Results Female mosquitoes sprayed with blastospores or conidia at a concentration of 108 propagules ml−1 were highly susceptible to both types of spores, resulting in 100% mortality within 7 days. However, significant differences in virulence of the isolates and propagules became apparent at 107 spores ml−1, with ESALQ 818 blastospores being more virulent than LEF 2000 blastospores. ESALQ 818 blastospores were highly virulent when mosquitoes were exposed to black cotton cloths impregnated with blastospores shortly after preparing the suspensions, but virulence declined rapidly 12 h post-application. The addition of vegetable oil to blastospores helped maintain virulence for up to 48 h. Conclusion The results showed that blastospores were more virulent to adult female Ae. aegypti than conidia when sprayed onto the insects or applied to black cloths. Vegetable oil helped maintain blastospore virulence. The results show that blastospores have potential for use in integrated vector management, although new formulations and drying techniques need to be investigated. Graphical abstract

Recently, advances have been made in the use of entomopathogenic fungi for the control of not only crop pests but also disease vectoring insects. New approaches, for example, combining control strategies such as the application of conventional insecticides and biological control agents together, are highly promising, especially as many insecticides are compatible with entomopathogenic fungi. In this review, we discuss some of the new approaches being developed for vector control. Governmental authorities must implement rational integrated vector management programs for reducing deaths and suffering caused by insect-vectored diseases. Although there are now many alternatives to conventional chemical control methods, the use of pesticides is still the mainstay of mosquito control measures. However, mosquitoes are rapidly developing resistance to the chemical insecticides in use at the moment. The deployment of entomopathogenic fungi for the control of all stages of the mosquito life cycle is an alternative strategy currently being investigated by many different research groups. It has been shown that entomopathogenic fungi can efficiently kill mosquito larvae and adults in laboratory and field conditions. However, an important aspect of this new approach is how to apply these biological control agents economically and efficiently. By using combinations of control agents and novel application systems, it may be possible to significantly reduce mosquito populations to levels at which epidemics of malaria, dengue fever, zika virus, and chikungunya do not occur.

BackgroundEntomopathogenic fungi are highly promising agents for controlling Aedes aegypti mosquitoes. Deploying fungus-impregnated black cloths in PET traps efficiently reduced Ae. aegypti female survival rates under intra-domicile conditions. With the aim of further increasing the effectiveness of the traps, the addition of attractive lures to fungus-impregnated traps was evaluated.MethodsBlack cloths were suspended inside 2 l plastic bottles called “PET traps”. These traps were placed in rooms simulating human residences. The first experiments evaluated the attraction of mosquitoes to PET traps with black cloths covered in adhesive film with and without synthetic lures (AtrAedes™). Traps were left in the test rooms for either 24 or 48 h. The attractiveness of the lures over time was also evaluated. The efficiency of PET traps with fungus-impregnated black cloths associated with lures was compared to that of traps without lures.ResultsThe highest percentage of captured mosquitoes (31 and 66%) were observed in PET traps with black cloths covered in adhesive film + attractive lure maintained in test rooms for 24 h and 48 h, respectively. Black cloths covered in adhesive film captured 17 or 36% of the mosquitoes at 24 h and 48 h, respectively. The attractiveness of the lures fell gradually over time, capturing 37% after 5 days on the bench and 22% of the mosquitoes after 30 days exposure to ambient conditions. Associating attractive synthetic lures with black cloths impregnated with M. anisopliae placed in test rooms for 120 h reduced mean survival to 32%, whilst black cloths impregnated with M. anisopliae without lures resulted in a 48% survival rate. Using Beauveria bassiana in the traps resulted in a 52% reduction in mosquito survival, whilst combining Beauveria and AtrAedes resulted in a 36% survival rate. PET traps impregnated with fungus + AtrAedes resulted in similar reductions in survival when left in the rooms for 24, 48, 72 or 120 h.ConclusionsAtrAedes increased attractiveness of PET traps with black cloths under intra-domicile conditions and when associated with M. anisopliae or B. bassiana, significantly reduced Aedes survival. This strategy will reduce the number of PET traps necessary per household.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2871-z) contains supplementary material, which is available to authorized users.

Background The entomopathogenic fungus Metarhizium anisopliae is a candidate for the integrated management of the disease vector mosquito Aedes aegypti . Metarhizium anisopliae is pathogenic and virulent against Ae. aegypti larvae; however, its half-life is short without employing adjuvants. Here, we investigated the use of neem oil to increase virulence and persistence of the fungus under laboratory and simulated field conditions. Methods Neem was mixed with M. anisopliae and added to recipients. Larvae were then placed in recipients at 5-day intervals for up to 50 days. Survival rates were evaluated 7 days after exposing larvae to each treatment. The effect of neem on conidial germination following exposure to ultraviolet radiation was evaluated under laboratory conditions. Statistical tests were carried out using ANOVA and regression analysis. Results Laboratory bioassays showed that the fungus alone reduced survival to 30% when larvae were exposed to the treatment as soon as the suspension had been prepared (time zero). A mixture of fungus + neem resulted in 11% survival at time zero. The combination of fungus + neem significantly reduced larval survival rates even when suspensions had been maintained for up to 45 days before adding larvae. For simulated-field experiments 1% neem was used, even though this concentration is insecticidal, resulting in 20% survival at time zero. However, this toxic effect was reduced over time. When used alone under simulated-field conditions the fungus rapidly lost virulence. The formulation fungus + neem effectively maintained fungal virulence, with larval survival rates significantly reduced for up to 45 days after preparation of the suspensions. The effective half-life of the fungus or neem when used separately was 6 and 13 days, respectively. The half-life of fungus formulated in 1% neem was 34 days. Conidia suspended in neem maintained high levels of germination even following a 2-h exposure to ultraviolet radiation. Conclusions A combination of the entomopathogenic fungus M. anisopliae with neem oil effectively increases the half-life and virulence of the fungus when tested against Ae. aegypti larvae, even under simulated field conditions. Neem oil also protected the fungus from the damaging effects of ultraviolet radiation. Electronic supplementary material The online version of this article (10.1186/s13071-019-3415-x) contains supplementary material, which is available to authorized users.

Resumo Darcy Ribeiro desafia a ausência de um modo singular de imaginação sociológica a caracterizar o pensamento brasileiro, não se deixando guiar por parâmetros exógenos ditados por uma pretensa modernidade que ignora a positividade das experiências aqui existentes. Tomando, de um lado, "O processo Civilizatório" (2001), e de outro, "O Povo Brasileiro" (1995