Effects of Glyphosate Herbicide on Physiological Parameters of Koi Carp, Cyprinus Carpio (Linnaeus, 1758) Fingerlings

Background: Sub-lethal toxicity bioassay experiments were conducted to determine the toxicity of glyphosate herbicide on Koi carp, Cyprinus carpio fingerlings. Koi carp fingerlings with mean length 8.06 ± 0.99 cm were obtained from a freshwater fish seed hatchery of the university.Methods: The fishes were exposed to sub-lethal concentrations i.e. 1/10th (3.6 mgL-1) and 1/5th (6.6 mgL-1) of glyphosate. Oxygen consumption rate, Ammonia-Nitrogen excretion rate, Oxygen:Nitrogen ratio and food consumption rate were recorded after every 7 days for a period of 28 days.Result: Results indicated significant decrease (P less than 0.05) in oxygen consumption in 1/10th and 1/5th of LC50 concentrations. Ammonia-Nitrogen significcantly increased in exposed fishes. Oxygen : Nitrogen ratio and food consumption rate also significantly decreased (P greater than 0.05) in treated fishes. The results indicated that glyphosate had impacts on exposed fish, hence, the need of regulation of its usage to protect non-targeted species and the environment.

MEDICIÓN INDIRECTA DE LA TASA DE CONSUMO DE ADULTOS E INMADUROS DE Trialeurodes vaporariorum (HEMIPTERA: ALEYRODIDAE) SOBRE FRÍJOL

<p>La biología y ecología de la mosca blanca de los invernaderos, <em>Trialeurodes vaporariorum </em>(Westwood) (Hemiptera: Aleyroridae), se encuentra ampliamente documentada. Sin embargo, hasta el momento no hay reportes acerca de la tasa de consumo de alimento por este fitófago, un parámetro necesario para modelos de simulación. Por tal motivo, el objetivo de esta investigación fue la medición indirecta del consumo de alimento por el adulto e instares inmaduros de <em>T. vaporariorum</em> basado en metodologías encontradas en la literatura científica. La estimación de la tasa de consumo de alimento por adultos se realizó bajo condiciones de laboratorio, utilizando como unidad experimental una planta de fríjol de dos semanas de edad. El experimento consistió de dos tratamientos: (T1) plantas libres de cualquier fitófago y (T2) plantas sometidas a infestaciones con <em>T. vaporariorum</em>, cada tratamiento con 20 repeticiones y una réplica en el tiempo de todo el experimento. Se registró el peso fresco diariamente en ambos tratamientos. Para el caso de los inmaduros, la unidad experimental consistió en una hoja cotiledónea de fríjol, infestada con una población determinada de inmaduros de cada instar de mosca blanca teniendo así cinco tratamientos (Instar I, II, III, IV y Control) cada uno con 17 repeticiones. Se registró diariamente el peso fresco de las hojas. Se obtuvo un consumo promedio de alimento por el adulto de 0,277 ± 0,0042 mg.dia^-1. Para los dos primeros instares ninfales se estimó una tasa de consumo de 0,052 mg.dia^-1, en el tercer instar de 0,14 mg.dia^-1, y para el cuarto instar de 0,19 mg.dia^-1. Un adulto de mosca blanca puede consumir en un día seis veces su peso y un inmaduro ocho veces, gracias a su rápido metabolismo y la constante excreción de mielecilla. </p><p><strong>Indirect Measurement of the</strong> <strong>Rate of Consumption of Adult and Immature of <em>Trialeurodes vaporariorum </em>(Hemiptera: Aleyrodidae) On Common Bean</strong></p><p>The biology and ecology of the greenhouse whitefly, <em>Trialeurodes vaporariorum </em>Westwood (Hemiptera: Aleyroridae), is widely documented. However, so far there are not reports about the rate of consumption of this phytophagous. Therefore, the objective of this research was to measure the food consumption by the adult and immature instars of <em>T. vaporariorum</em> based on indirect methodologies found in the literature. The estimate of the food consumption rate by adults was conducted under laboratory conditions, using as experimental units plant beans two weeks old. The experiment consisted of two treatments: (T1) plants free from any phytophagous and (T2) plants subjected to infestation with <em>T. vaporariorum</em>, with 20 repetitions each treatment and replicated over time. In the case of the immature individuals, the experimental unit consisted of a bean cotyledon leaf infested with a population of immature individuals of each instar of whitefly, having five treatments (Instar I, II, III, IV and Control) each with 17 repetitions. Fresh weight of leaves was recorded daily. An average food consumption of 0.277 ± 0.0042 mg.day^-1 was obtained for the adult. For the first two nymphal instars food consumption rate of 0.052 mg.day^-1 was estimated, for the third instar 0.14 mg.day^-1, and for the fourth instar 0.19 mg.day^-1. An whitefly adult can consume in a day six times its weight and an immature eight times, this thanks to the rapid metabolism and a constant excretion of honeydew of the species.</p>