Characterization of spatial distribution of Tetranychus urticae in peppermint in California and implication for improving sampling plan.

Twospotted spider mite, Tetranychus urticae Koch, is an important pest of peppermint in California, USA. Spider mite feeding on peppermint leaves causes physiological changes in the plant, which coupling with the favorable environmental condition can lead to increased mite infestations. Significant yield loss can occur in absence of pest monitoring and timely management. Understating the within-field spatial distribution of T. urticae is critical for the development of reliable sampling plan. The study reported here aims to characterize the spatial distribution of mite infestation in four commercial peppermint fields in northern California using spatial techniques, variogram and Spatial Analysis by Distance IndicEs (SADIE). Variogram analysis revealed that there was a strong evidence for spatially dependent (aggregated) mite population in 13 of 17 sampling dates and the physical distance of the aggregation reached maximum to 7 m in peppermint fields. Using SADIE, 11 of 17 sampling dates showed aggregated distribution pattern of mite infestation. Combining results from variogram and SADIE analysis, the spatial aggregation of T. urticae was evident in all four fields for all 17 sampling dates evaluated. Comparing spatial association using SADIE, ca. 62% of the total sampling pairs showed a positive association of mite spatial distribution patterns between two consecutive sampling dates, which indicates a strong spatial and temporal stability of mite infestation in peppermint fields. These results are discussed in relation to behavior of spider mite distribution within field, and its implications for improving sampling guidelines that are essential for effective pest monitoring and management.

Actividad in vivo del mentol frente a larvas l3 de Anisakis tipo I / In vivo larvicidal activity of menthol against Anisakis type I

Se ha estudiado la actividad larvicida in vivo de mentol, principal componente del aceite esencial de Mentha pipperita, frente a larvas de Anisakis tipo I aisladas del hospedador Micromesistius poutassou (bacaladilla), adquiridas en diversas pescaderías de la ciudad de Granada. Los resultados obtenidos en el ensayo muestran que en el grupo tratado con mentol no se apreciaron lesiones en el aparato digestivo, mientras que en el grupo control estas lesiones fueron observadas en el 93’3% de los animales de experimentación. En este mismo grupo se encontraron larvas que habían perforado la pared gástrica, localizándose libres en la cavidad corporal(AU)

We have studied the in vivo larvicidal activity of menthol, the main component of the essential oil of Mentha pipperita, against Anisakis type I larvae isolated from the host Micromesistius poutassou(blue whiting), acquired in several fishmongers in the city of Granada. The in vivo test results showed no gastric wall lesions in the group treated with menthol, while in the control group, 93.3% of infected rats showed those lesions. In the same control group were found larvae that had drilled the gastric wall, located free in the abdominal cavity(AU)

Actividad antiparasitaria de una decocción de Mentha piperita Linn / Antiparasitic activity of a Mentha piperita Linn

Con el objetivo de comprobar si la Mentha piperita Linn posee efecto antiparasitario, se valoró una decocción de las hojas de esta planta. El modelo biológico utilizado fue la lombriz terrestre del género rojo California y las dosis empleadas fueron 0,475; 0,950 y 1,900 g/dL. Se formaron además un grupo control negativo (agua destilada) y un grupo control positivo (solución de piperazina al 2,0 por ciento). La evaluación, en placa Petri, se realizó de forma continua durante un período de 8 h. La variable medida fue tiempo de supervivencia y se expresó en minutos. Los resultados demuestran que la decocción de las hojas de Mentha piperita Linn posee efecto vermífugo en dependencia de la dosis. La dosis máxima resultó ser más potente que la droga de referencia empleada (piperazina 2,0 por ciento). El nivel de significación se fijó en una p £ 0,05(AU)