Comparison of two commercial formulations of Bacillus thuringiensis var. israelensis for the control of Anopheles aquasalis (Diptera: Culicidae) at three salt concentrations

Osborn, Frances; Herrera, Melfrán; Gómez, Cruz; Salazar, Armando

doi:10.1590/s0074-02762007000100011

Cited by 16 publications

(12 citation statements)

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“…thuringiensis toxin for the control of salinity-tolerant malaria vector Anopheles aquasalis at different salt concentrations revealed an increase in the LC 50 for B . thuringiensis at higher salt concentrations [26]. Our results suggest that crystal formulation of B .…”

Section: Discussionmentioning

confidence: 86%

Salinity-tolerant larvae of mosquito vectors in the tropical coast of Jaffna, Sri Lanka and the effect of salinity on the toxicity of Bacillus thuringiensis to Aedes aegypti larvae

et al. 2012

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BackgroundDengue, chikungunya, malaria, filariasis and Japanese encephalitis are common mosquito-borne diseases endemic to Sri Lanka. Aedes aegypti and Aedes albopictus, the major vectors of dengue, were recently shown to undergo pre-imaginal development in brackish water bodies in the island. A limited survey of selected coastal localities of the Jaffna district in northern Sri Lanka was carried out to identify mosquito species undergoing pre-imaginal development in brackish and saline waters. The effect of salinity on the toxicity of Bacillus thuringiensis israelensis larvicide to Ae. aegypti larvae at salinity levels naturally tolerated by Ae. aegypti was examined.MethodsLarvae collected at the selected sites along the Jaffna coast were identified and salinity of habitat water determined in the laboratory. The LC50 and LC90 of B. thuringiensis toxin, the active ingredient of a commercial formulation of the larvicide BACTIVEC®, were determined with Ae. aegypti larvae. Bioassays were also carried out at salinities varying from 0 to18 ppt to determine the toxicity of Bacillus thuringiensis to fresh and brackish water-derived larvae of Ae. aegypti.ResultsLarvae of four Anopheles, two Aedes, one Culex and one Lutzia species were collected from brackish and saline sites with salinity in the range 2 to 68 ppt. The LC50 and LC90 of B. thuringiensis toxin for the second instar larvae of Ae. aegypti in fresh water were 0.006 ppm and 0.013 ppm respectively, with corresponding values for brackish water populations of 0.008 and 0.012 ppm respectively. One hundred percent survival of second instar fresh water and brackish water-derived Ae. aegypti larvae was recorded at salinity up to 10 and 12 ppt and 100% mortality at 16 and 18 ppt, yielding an LC 50 for salinity of 13.9 ppt and 15.4 ppt at 24 h post-treatment respectively for the two populations. Statistical analysis showed significantly reduced toxicity of B. thuringiensis to fresh and brackish water-derived Ae. aegypti larvae at high salinities.ConclusionA variety of mosquito vectors of human diseases undergo pre-imaginal development in brackish or saline waters in coastal areas of the Jaffna district in northern Sri Lanka. Salinity has a small but significant negative impact on the toxicity of B. thuringiensis toxin to Ae. aegypti larvae at salinity levels where Ae. aegypti larvae are found in the environment. This has implications for the use of B. thuringiensis toxin as a larvicide in brackish waters.

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Section: Discussionmentioning

confidence: 86%

Salinity-tolerant larvae of mosquito vectors in the tropical coast of Jaffna, Sri Lanka and the effect of salinity on the toxicity of Bacillus thuringiensis to Aedes aegypti larvae

et al. 2012

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“…Studies to understand the lethal action of commercial or new formulations of bio-insecticides with Bti-based active principles are conducted regularly (Ibarra et al, 2003;Praça et al, 2004;Lima et al, 2005;Osborn et al, 2007). However, the target-species in experiments vary according to the mosquito species of major health concern in each region.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of a new formulation of Bacillus thuringiensis israelensis

2010

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The aim of this study was to determine the potency (ITU) and efficacy of a liquid formulation of Bacillus thuringiensis israelensis developed by the State University of Londrina named BioUel, against early fourth instar larvae of Aedes aegypti and Culex quinquefasciatus. The ITU/mg of BioUel was 960, the LC50 was of 0.271 (± 0.39) ppm, and the LC95 was 0.634 (± 0.099) ppm, in larvae of C. quinquefasciatus. In A. aegypti larvae, LC50 was 0.332 (± 0.042) ppm and LC95 was 0.694 (± 0.073) ppm. The ITU level of BioUel and its control results were similar to most commercial products tested. Stability was of approximately 90 days, which allows for local production.

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“…Berliner e Bacillus sphaericus Neide fazem parte de um complexo de linhagens bacterianas que produzem toxinas ativas para larvas de mosquitos (Charles et al 1996;Capalbo et al 2004;brar et al 2006;Gammon et al 2006;Osborn et al 2007). Produtos comerciais, possuindo os cristais produzidos por essas bactérias como princípio ativo, são amplamente utilizados em diferentes formulações para controle de espécies de mosquito vetores de patógenos (laCey 1984;yap et al 1991;alves et al 1999;DominiC amalraj et al 2000;alves et al 2001;DelGaDo et al 2001;alves et al 2006;osborn et al 2007).…”

Section: B Acillus Thuringiensis Israelensisunclassified

“…Produtos comerciais, possuindo os cristais produzidos por essas bactérias como princípio ativo, são amplamente utilizados em diferentes formulações para controle de espécies de mosquito vetores de patógenos (laCey 1984;yap et al 1991;alves et al 1999;DominiC amalraj et al 2000;alves et al 2001;DelGaDo et al 2001;alves et al 2006;osborn et al 2007).…”

Section: B Acillus Thuringiensis Israelensisunclassified

Eficiência e Persistência de Três Produtos Comerciais à Base de <i>Bacillus thuringiensis israelensis</i> e <i>Bacillus sphaericus</i> no controle de Culicidae (Diptera) em Lagoas de Tratamento de Efluentes

et al. 2010

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S a ú d E P ú B l I c aResumo. A ação hematofágica exercida por fêmeas de algumas espécies de Culicidae sobre o homem e outros animais pode estar diretamente relacionada à transmissão de patógenos, além de provocar reações alérgicas e causar incômodo. O aparecimento de populações resistentes aos inseticidas químicos impulsiona o uso de métodos de controle alternativos, principalmente o biológico. Objetivando testar a eficiência e persistência de produtos comerciais com principio ativo a base de Bacillus thuringiensis israelensis Berliner e Bacillus sphaericus Neide foram realizados experimentos em três lagoas de tratamento de efluentes, sobre larvas de Culicidae. Testou-se Vectolex (formulação granulada de B. sphaericus), Sphaericus (formulação líquida de B. sphaericus) e Bt-horus (formulação líquida de B. thuringiensis). As aplicações foram realizadas quinzenalmente com avaliações realizadas a 0, 24, 48, 72 e 120 horas após a aplicação. As lagoas estavam colonizadas por Culex nigripalpus Theobald (1,5%), Culex saltanensis Dyar (2,25%) e Culex quinquefasciatus Say (96,25%). Com o produto Bt horus, registrou-se redução larval de 89,06%, 83,97% e 89,96% respectivamente a 24, 48 e 72 horas após a aplicação. Nos produtos contendo B. sphaericus, respectivamente na formulação granulada e líquida observou-se uma redução de 98,89% e 98,34%, após 24 horas da aplicação e de 99,79% e 99,78% após 48 horas. Os produtos e as diferentes formulações foram eficientes no controle de larvas das três espécies de culicídeos em lagoas com grande quantidade de matéria orgânica, porém a persistência verificada foi de dois e três dias para produtos contendo respectivamente B. sphaericus e B. thuringiensis israelensis. Palavras-Chave: Água poluída; Controle biológico; Culex Efficiency and Persistence of Three Commercial Products Based on Bacillus thuringiensis israelensis and Bacillus sphaericus in Controlling Culicidae (Diptera) in Effluent Treatment LagoonsAbstract. The hematofagic effect caused by females belonging to some species of Culicidae on humans and animals can be directly related to pathogen transmission, allergic reactions and uneasiness. The emergence of populations resistant to chemical insecticides has fostered the use of alternative methods, mainly biological control. The trials were conducted in three effluent treatment lagoons, on larvae of Culicidae to test the efficiency and persistence of commercial products whose active principles are based on Bacillus thuringiensis israelensis Berliner and Bacillus sphaericus Neide. The products tested were Vectolex (a granulated formulation of B. sphaericus), Sphaericus (a liquid formulation of B. sphaericus) and Bt-horus (a liquid formulation of B. thuringiensis). The products were applied biweekly and evaluations were conducted 0, 24, 48, 72, and 120 hours after each application. The lagoons were colonized by Culex nigripalpus Theobald (1.5%), Culex saltanensis Dyar (2.25%), and Culex quinquefasciatus Say (96.25%). Bt horus reduced larvae by 89.06%, 83.97% and 89.96% at 24, 48 ...

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Comparison of two commercial formulations of Bacillus thuringiensis var. israelensis for the control of Anopheles aquasalis (Diptera: Culicidae) at three salt concentrations

Cited by 16 publications

References 4 publications

Salinity-tolerant larvae of mosquito vectors in the tropical coast of Jaffna, Sri Lanka and the effect of salinity on the toxicity of Bacillus thuringiensis to Aedes aegypti larvae

Salinity-tolerant larvae of mosquito vectors in the tropical coast of Jaffna, Sri Lanka and the effect of salinity on the toxicity of Bacillus thuringiensis to Aedes aegypti larvae

Evaluation of a new formulation of Bacillus thuringiensis israelensis

Eficiência e Persistência de Três Produtos Comerciais à Base de <i>Bacillus thuringiensis israelensis</i> e <i>Bacillus sphaericus</i> no controle de Culicidae (Diptera) em Lagoas de Tratamento de Efluentes

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