Lethal and Sublethal Effect Caused by a Citric Extract on Demotispa neivai (Coleopteran: Chrysomelidae)
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Author
Martínez, Luis C.
Valencia C., Carolina
Aldana de la Torre, Rosa C.
Como citar
Publicación:
Revista Palmas; Vol. 29 Núm. 1 (2008); 39-46
0121-2923
Revista Palmas; Vol. 29 Núm. 1 (2008); 39-46
0121-2923
Abstract
Research for the development of management practices is required on many of the oil palm pest insects. Among these is Demotispa neivai Bondar, known as oil palm fruit scraper. In seeking alternatives for the insect control, a natural product consisting of citric juice, pulp and seeds combined with glycerine, without restriction for its agroindustrial and environmental use, was used. The product is a viscous biodegradable liquid with a high molecular weight made up of ingredients such as ascorbic and citric acids. Laboratory bioassays were conducted in order to evaluate the biocidal capacity of the citric extract on adult D. neivai insects. The repellent effect of the product applied at different concentrations on oil palm fruit was evaluated. The fruit was placed on a tray in which concentric circles, 3.5 cm apart from each other, were drawn The lethal effect was evaluated by determining the mean lethal dose LD50 and mean lethal time LT50. The treatments applied were five solutions of the product at different concentrations per liter of water: 35, 70, 105, 140 and 175 ml and a control with distilled water. The antifeedant effect was estimated by measuring the area of the fruit consumed by the insect with a millimetric mesh every three days, in each of the evaluated treatments. The product did not have a repellent effect on the insect, lethal time TL50 presented itself after 37.8 hours and it stabilized eight days after the application. The mean lethal dose LD50 was 80.1 ml with an upper and lower 95% confidence limit between 70.2 and 89.4 ml. Additionally, it showed an antifeedant effect which accentuated progressively as the concentration of the product was increased. The results enabled to verify the lethal effect of the citric extract on D. neivai adults at concentrated doses of the product. Muchos de los insectos plaga de la palma de aceite requieren de investigación que permita generar prácticas para su manejo. Entre estos se encuentra Demotispa neivai Bondar, conocido como raspador del fruto de la palma de aceite. En la búsqueda de alternativas para el control del insecto, se empleó un producto natural de jugos, pulpa y semillas de cítricos en combinación con glicerina, sin restricción para su uso agroindustrial y ambiental. El producto es un líquido viscoso biodegradable, con un alto peso molecular compuesto por ingredientes como los ácidos ascórbico y cítrico. Se realizaron bioensayos en laboratorio para evaluar la capacidad biocida del extracto de cítricos en insectos adultos de D. neivai. Se evaluó el efecto repelente del producto aplicado a diferentes concentraciones sobre frutos de la palma de aceite ubicados en una bandeja en la que se delinearon círculos concéntricos con distancias de 3,5 cm entre cada uno. El efecto letal se evaluó determinando la dosis letal media DL50 y tiempo letal TL50. Los tratamientos aplicados fueron cinco soluciones del producto a diferentes concentraciones por litro de agua: 35, 70, 105, 140 y 175 mL y un testigo con agua destilada. El efecto antialimentario se calculó, midiendo con una malla milimetrada, el área consumida de los frutos por el insecto cada tres días, en cada uno de los tratamientos evaluados. El producto no tuvo un efecto repelente en el insecto, el tiempo letal TL50 se presentó a las 37,8 horas y se estabilizó ocho días después de la aplicación. La dosis letal media DL50 fue de 80,1 mL con un límite superior e inferior de confianza al 95por ciento entre 70,2 y 89,4 mL. Además, presentó un efecto antialimentario que se acentuó en forma progresiva en la medida en que se incrementó la concentración del producto. Los resultados permitieron verificar el efecto letal del extracto de cítricos en adultos de D. neivai a dosis concentradas del producto.
Research for the development of management practices is required on many of the oil palm pest insects. Among these is Demotispa neivai Bondar, known as oil palm fruit scraper. In seeking alternatives for the insect control, a natural product consisting of citric juice, pulp and seeds combined with glycerine, without restriction for its agroindustrial and environmental use, was used. The product is a viscous biodegradable liquid with a high molecular weight made up of ingredients such as ascorbic and citric acids. Laboratory bioassays were conducted in order to evaluate the biocidal capacity of the citric extract on adult D. neivai insects. The repellent effect of the product applied at different concentrations on oil palm fruit was evaluated. The fruit was placed on a tray in which concentric circles, 3.5 cm apart from each other, were drawn The lethal effect was evaluated by determining the mean lethal dose LD50 and mean lethal time LT50. The treatments applied were five solutions of the product at different concentrations per liter of water: 35, 70, 105, 140 and 175 ml and a control with distilled water. The antifeedant effect was estimated by measuring the area of the fruit consumed by the insect with a millimetric mesh every three days, in each of the evaluated treatments. The product did not have a repellent effect on the insect, lethal time TL50 presented itself after 37.8 hours and it stabilized eight days after the application. The mean lethal dose LD50 was 80.1 ml with an upper and lower 95% confidence limit between 70.2 and 89.4 ml. Additionally, it showed an antifeedant effect which accentuated progressively as the concentration of the product was increased. The results enabled to verify the lethal effect of the citric extract on D. neivai adults at concentrated doses of the product.
Palabras clave:
palma de aceite
elaeis guineensis
control de plagas
insectos dañinos
coleóptera
chrysomelidae
palma de aceite
elaeis guineensis
control de plagas
insectos dañinos
coleóptera
chrysomelidae