RESIDUALIDAD DE TRES FORMULACIONES DE Bacillus thuringiensis SH-14 VAR. ISRAELENSIS CULTIVADO EN “SANGUAZA” SOBRE EL PORCENTAJE DE MORTALIDAD EN LARVAS DE Aedes aegypti
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Date
2010
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Universidad Nacional de Trujillo
Abstract
La acción biocida de Bacillus thuringiensis SH-14 var. Israelensis (Bti) frente a las larvas de Aedes aegypti, ha sido investigada a partir de su descubrimiento, sin embargo su actividad residual y el elevado costo de producción y formulación ha sido hasta hoy una de las desventajas por la cual su aplicación no ha sido del todo exitosa. En este contexto, la presente investigación tuvo por objetivo evaluar la residualidad de tres formulaciones de Bacillus thuringiensis Sh – 14 var. Israelensis cultivada en “sanguaza” sobre el porcentaje de mortalidad en larvas de A. aegypti, para tal efecto se elaboraron tres formulaciones de Bti con biopolímeros; harina de maíz morado, carragenina y su combinación a 0.5 y 2% de ingrediente activo (i.a.), exponiéndose a las larvas de tercer estadio A. aegypti a 0.1g de cada formulación, la mortalidad de larvas se registró mediante observación directa a las 48 horas de aplicados los tratamientos, luego fueron cuidadosamente removidas con una pipeta plástica, posteriormente un lote nuevo de 25 larvas de A. aegypti se introdujeron en los contenedores a los 1, 10, 20, 30, 40, 50 y 60 días post aplicación de las formulaciones. Los resultados muestran el aumento de la residualidad de Bti al formularlo en harina de maíz morado a 2% de i.a. produciendo una LT/50 hasta los 28 días postaplicación, asimismo la formulación Bti – carragenina a 2% de ia, produjo la mínima residualidad que se expresa en una LT/50 después de 2 días de aplicado el tratamiento. Por su parte, la formulación Bti – maíz morado – carragenina logró una LT/50 hasta los 18 días postratamiento. Por lo tanto la formulación Bti – maíz morado a 2% de i.a resulto con mayor residualidad, posiblemente debido al efecto fotoprotector de las antocianinas contenidas en el biopolímero.
The action biocida of Bacillus thuringiensis SH-14 var. Israelensis (Bti) in front of the larvas of Aedes aegypti, it has been investigated starting from their discovery, however their residual activity and the high production cost and formulation has been until today one of the disadvantages for which its application has not been completely successful. In this context, the present investigation had for objective to evaluate the residualidad of three formulations of Bacillus thuringiensis Sh - 14 var. Israelensis cultivated in "sanguaza" on the percentage of mortality in larvas of A. aegypti, for such an effect three formulations of Bti were elaborated with biopolímeros; flour of lived corn, carragenina and their combination to 0.5 and 2% of active ingredient (i.a.), being exposed the larvas of third stadium A. aegypti to 0.1g of each formulation, the mortality of larvas registered by means of direct observation at the 48 hours of having applied the treatments, then they were carefully removed with a plastic pipette, later on a new lot of 25 larvas of A. aegypti was introduced in the containers at the 1, 10, 20, 30, 40, 50 and 60 days post application of the formulations. The results show the increase of the residualidad from Bti when formulating it in flour of corn lived to 2% of i.a. producing a LT/50 until the 28 days postaplicación, also the formulation Bti - carragenina to 2 ia%, the minimum residualidad that is expressed in a LT/50 after 2 days of having applied the treatment took place. On the other hand, the formulation Bti - lived corn - carragenina achievement a LT/50 until the 18 days postratamiento. Therefore the formulation Bti - corn lived to 2% of i.a is with more residualidad, possibly due to the effect fotoprotector of the antocianinas contained in the biopolímero.
The action biocida of Bacillus thuringiensis SH-14 var. Israelensis (Bti) in front of the larvas of Aedes aegypti, it has been investigated starting from their discovery, however their residual activity and the high production cost and formulation has been until today one of the disadvantages for which its application has not been completely successful. In this context, the present investigation had for objective to evaluate the residualidad of three formulations of Bacillus thuringiensis Sh - 14 var. Israelensis cultivated in "sanguaza" on the percentage of mortality in larvas of A. aegypti, for such an effect three formulations of Bti were elaborated with biopolímeros; flour of lived corn, carragenina and their combination to 0.5 and 2% of active ingredient (i.a.), being exposed the larvas of third stadium A. aegypti to 0.1g of each formulation, the mortality of larvas registered by means of direct observation at the 48 hours of having applied the treatments, then they were carefully removed with a plastic pipette, later on a new lot of 25 larvas of A. aegypti was introduced in the containers at the 1, 10, 20, 30, 40, 50 and 60 days post application of the formulations. The results show the increase of the residualidad from Bti when formulating it in flour of corn lived to 2% of i.a. producing a LT/50 until the 28 days postaplicación, also the formulation Bti - carragenina to 2 ia%, the minimum residualidad that is expressed in a LT/50 after 2 days of having applied the treatment took place. On the other hand, the formulation Bti - lived corn - carragenina achievement a LT/50 until the 18 days postratamiento. Therefore the formulation Bti - corn lived to 2% of i.a is with more residualidad, possibly due to the effect fotoprotector of the antocianinas contained in the biopolímero.
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Keywords
Bacteria, toxina, poder residual, radiación