SUMMARY Thrips and aphids are among the important sanitary limitations to lettuce crop (Lactuca sativa L.) production in the Green Belt of Córdoba (CVC) (Córdoba, Argentina). The objectives of this work were: a) to evaluate the attraction efficiency of blue, white and yellow sticky traps for thrips and aphids in lettuce crops, b) to characterize the correlation between the catches of aphids and thrips in the traps and the density of these insects in lettuce plants, and c) to determine the utility of chromatic adhesive traps for the evaluation of different pest management treatments. After two years of field tests (20182019 and 2019-2020) in conventional and agroecological farms in the CVC, it was determined that blue and white traps were the most effective against thrips, and yellow traps were the most effective against aphids. As for thrips, traps proved to be a useful tool for monitoring these pests since a positive correlation was observed between captures in traps and their density in the crop. The response of aphid populations for garlic extract and chemical control treatments did not differ statistically, suggesting the potential of this bioinput as a lettuce management tool in conventional crops.

RESUMEN Trips y pulgones se encuentran entre las principales limitaciones sanitarias para la producción de lechuga (Lactuca sativa L.) en el Cinturón Verde de Córdoba (CVC) (Córdoba, Argentina). Los objetivos de este trabajo fueron: a) evaluar la eficacia de atracción de trampas adhesivas de color azul, blanco y amarillo para trips y pulgones en el cultivo de lechuga, b) caracterizar la correlación entre las capturas de pulgones y trips en las trampas y la densidad de estos insectos en plantas de lechuga y c) determinar la utilidad de las trampas adhesivas cromáticas para la evaluación de distintos tratamientos sanitarios. Por medio de ensayos realizados durante dos campañas (20182019 y 2019-2020) en establecimientos productivos con manejo convencional y agroecológico, se determinó que las trampas azules y blancas fueron las más eficientes para trips, y las trampas amarillas para pulgones. En el caso de trips, pueden ser una herramienta útil para su monitoreo en el cultivo, en tanto se observó una correlación positiva entre capturas en trampas y su densidad en plantas. La respuesta observada en pulgones para ajo y control químico no difiere estadísticamente, lo que sugiere el potencial de este bioinsumo como alternativa para lechuga en planteos de manejo convencional.

The influence of the ionic adsorption on the anchoring energy of a nematic liquid crystal sample is investigated. We determine the behavior of the anchoring energy as a function of the thickness of the sample, and as a function of the adsorption energy of ions. We show that the contribution to the anchoring energy, due to ionic adsorption, can be of the same order of magnitude of the bare anchoring strength. Our analysis generalizes similar calculations previously published by incorporating the effect of adsorbed charges on the potential and field profiles in the sample.