Larval Susceptibility of Two Culex quinquefasciatus Populations (Diptera: Culicidae) Temephos® in the City of Naviraí, MS, Brazil

The control mosquito populations in Brazil is needed to prevent disease transmission and nuisance to man, and avoid causing deaths and economic losses.  The susceptibility of two populations of Culex quinquefasciatus to the larvicide temephos was evaluated. Larvae were collected in septic tanks at the neighborhoods of Vila Nova and Varjão (Naviraí, Mato Grosso do Sul, Brazil), and submitted to different concentrations of the insecticide, being possible to calculate lethal concentrations. The results showed that there is resistance to this organophosphate, when considering the degree of mortality at the diagnosis concentration (DC), indicated by WHO, what was confirmed by the high values found for LCs. We discussed the role of larvicide in national dengue control program and the agricultural use of organophosphates in the region. The results indicate the need to adopt integrated management practices vectors against this mosquito that causes discomfort. DOI: http://dx.doi.org/10.17807/orbital.v7i3.74

Larval Susceptibility of Two Culex quinquefasciatus Populations (Diptera: Culicidae) Temephos® in the City of Naviraí, MS, Brazil

The control mosquito populations in Brazil is needed to prevent disease transmission and nuisance to man, and avoid causing deaths and economic losses.  The susceptibility of two populations of Culex quinquefasciatus to the larvicide temephos was evaluated. Larvae were collected in septic tanks at the neighborhoods of Vila Nova and Varjão (Naviraí, Mato Grosso do Sul, Brazil), and submitted to different concentrations of the insecticide, being possible to calculate lethal concentrations. The results showed that there is resistance to this organophosphate, when considering the degree of mortality at the diagnosis concentration (DC), indicated by WHO, what was confirmed by the high values found for LCs. We discussed the role of larvicide in national dengue control program and the agricultural use of organophosphates in the region. The results indicate the need to adopt integrated management practices vectors against this mosquito that causes discomfort. DOI: http://dx.doi.org/10.17807/orbital.v7i3.74

A Simple Method For Immobilising Small Dipteran Insects And Its Validation For Aedes Aegypti

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A simple method for immobilising small dipteran insects and its validation for Aedes aegypti

Univ Estadual Campinas, Inst Biol, Dept Anim Biol, BR-13083862 Campinas, SP, BrazilFed Univ Grande Dourados, Fac Exact Sci & Technol, Dourados, MS, BrazilUniv Estadual Paulista, Fac Agr & Vet Sci, Jaboticabal, SP, BrazilUniv Estadual Paulista, Fac Agr & Vet Sci, Jaboticabal, SP, Brazi

Avaliação da Susceptibilidade ao Temephos de Populações de Aedes aegypti (Diptera: Culicidae) dos Municípios de Maracaju e Naviraí, MS, Brasil

Dengue é uma das arboviroses mais importante no mundo atualmente, cuja transmissão se dá pela picada do mosquito Aedes aegypti. O controle do vetor, com produtos biológicos ou químicos, ainda é a principal forma de controle, sendo os inseticidas uma importante ferramenta nos programas de manejo integrado. Porém, esta estratégia encontra-se ameaçada pela seleção de resistência, especialmente aos organofosforados. O objetivo com o presente trabalho foi avaliar o status de susceptibilidade/resistência de populações de Ae. aegypti ao organofosforado Temephos® em dois municípios onde ocorre uso contínuo desse inseticida. Utilizou-se as concentrações diagnóstico 0,008 e 0,012 mg L-1 como preconizado, respectivamente, pela Superintendência de Controle de Endemias do Estado de São Paulo (SUCEN) e pela Organização Mundial da Saúde (OMS). Os resultados apresentaram percentual de mortalidade abaixo de 80% nas duas concentrações avaliadas, demonstrando resistência das populações ao inseticida. Este fato aponta para a necessidade de monitoramento da resistência nas populações de Ae. aegypti da região.</jats:p

Evaluation of Eosin-Methylene Blue as a Photosensitizer for Larval Control of Aedes aegypti by a Photodynamic Process

Aedes aegypti (Ae. aegypti) is a competent vector for transmitting important viral diseases such as yellow fever, dengue, chikungunya, and Zika. Several strategies have been applied to avoid Ae. aegypti proliferation by using environmental management, biological, and chemical approaches. However, the development of new methods for effective control of the insect vector population is still needed. Photodynamic control is an alternative way to control the vector population by using a physical approach based on the larval phototoxicity of a photosensitizer. In this context, the present study evaluated the use of eosin-methylene blue (EMB) as a new photosensitizer for photodynamic control of Ae. aegypti larval populations. The photodynamic assays were performed submitting Ae. aegypti third-instar larvae to different EMB concentrations (0.0, 0.5, 1.0, 5.0, 10.0, 50.0, and 100.0 &micro;g mL&minus;1) in combination of three different light doses (24.3, 48.6, and 97.2 J cm&minus;2) under either white-light radiation from RGB LEDs or sunlight. The results demonstrated that EMB presented a rapid internalization into the larvae and was phototoxic. The photodynamic action induced 100% of larval mortality after about 40 min of sunlight irradiation even using low EMB concentration (0.5 &micro;g mL&minus;1). The findings reveal EMB as an effective photoactive compound to control larval populations of Ae. aegypti by photodynamic process induced by either sunlight or white-light from RGB LEDs