Fluctuación poblacional de la escama blanca del mango (Aulacaspis tubercularis Newstead) en Veracruz, México

Los estudios se realizaron, de 2012 a 2013 en huertos comerciales de mango manila en tres localidades de Veracruz, México; (Actopan, Cotaxtla y Tierra Blanca); con el objetivo de obtener información sobre la fluctuación de población anual de la escama blanca del mango. El monitoreo de las poblaciones se realizó cada quince días, en cada huerto se muestrearon cinco árboles a los cuales se marcaron cuatro ramas con orientación a cada punto cardinal. Se encontró que la especie que ataca al mango en Veracruz es Aulacaspis tubercularis Newstead (Hemíptera: Diaspididae), misma que se presenta en Nayarit, México. Respecto a la fluctuación poblacional se observaron dos eventos de crecimiento poblacional una de baja densidad desde el mes de julio periodo de lluvias, hasta el mes de enero y la segunda de incremento poblacional floreció de febrero a mayo, sin embargo en marzo se detectaron diferencias significativas en las tres localidades en el número de escamas (hembras), el promedio significativamente más alto por hoja (11.32) se registró en Actopan, seguido por Tierra Blanca (4.27) y finalmente en Cotaxtla (0.89). En cuanto a las colonias de escama (machos) se detectaron diferencias significativas en marzo; Actopan registró la infestación más alta de colonias por hoja (4.12), y la más baja Cotaxtla (0.89) superado por Tierra Blanca (2.92); los resultados muestran que las tres localidades fueron susceptibles a la escama blanca

POPULATION FLUCTUATION OF WHITE MANGO SCALE (Aulacaspis tubercularis Newstead) AND ITS NATURAL ENEMIES IN ‘MANILA’ MANGO ORCHARDS

Background. White mango scale (WMS) is present at any physiological stage of the mango tree, can remain on leaves and fruits, and affects photosynthesis and fruit aesthetics. Knowing the population fluctuation of WMS and its natural enemies over time will help to design efficient control strategies. Objective. To determine the annual population fluctuation of WMS and its natural enemies in three mango-producing areas, in Veracruz, Mexico. Methodology. In three mango orchards cv. 'Manila' in productive stage, located in the municipalities of Actopan, Medellín, and Tierra Blanca (one orchard at each municipality), the number of female individuals and male colonies of WMS, and its natural enemies Chilocorus cacti, Scymnus spp., Azya orbigera, Ceraeochrysa spp. and Pentilia spp., were monitored for 12 consecutive months. Results. Higher densities of WMS and Ceraeochrysa spp. were found in the Actopan orchard. The density of natural enemies changed according to species and time of year. The density of Pentilia spp., Scymnus spp., and Ceraeochrysa spp. correlated with the WMS density, with a higher and lower density of individuals per leaf in December-May and June-October, respectively. Implications. The time when the highest and lowest populations of WMS and its natural enemies occur in different 'Manila' mango-producing areas in Veracruz were identified. This knowledge will help to define the most appropriate timing and strategy for WMS control. Conclusion. The greater WMS population coincides with the fruiting stage, so its control should start in winter, during the flowering stage. Considering that the population of C. cacti, Pentilia sp., Scymnus spp., and Ceraeochrysa spp. present positive correlation with the WMS, it is recommended to reduce the use of broad-spectrum pesticides and to increase the use of cultural practices to benefit the population of these natural enemies

Análisis petrosísmico 3D de las formaciones Dallas, Houston base y París, bloque 8 del campo Cloudspin

Tesis (Licenciatura en Geología, Licenciatura en Geofísica), Instituto Politécnico Nacional, ESIA, Unidad Ticomán, 2018, 1 archivo PDF, (79 páginas). tesis.ipn.m

A Cost-Effective Methodology for Sizing Solar PV Systems for Existing Irrigation Facilities in Chile

In the last five years, the Chilean Ministries of Agriculture and Energy developed a national strategy to incorporate renewable energies into various economic sectors. Since 2013, more than 1500 off-grid solar photovoltaic (PV) systems, with power ranging from 1 kW to 3 kW, were installed to drive existing irrigation systems in small and medium-sized farms for the exportation of fresh fruit. A net billing regulation was also implemented in 2014. This study shows a cost-effective methodology for the sizing of solar PV systems for existing irrigation facilities in Chile, in an effort to improve the competitiveness of the fresh-fruit industry. The same methodology may also be implemented in other Latin American countries. The article presents the analysis of four projects (two in the Atacama Region, and two in the Maule Region). The baseline situation of the four units was studied, as well as the energy-efficient actions that may be applied, in addition to the recommended characteristics of the selected PV system to drive the irrigation systems of small fresh-fruit farms. Off-grid and on-grid solar PV systems were analyzed, including some particularities of the Chilean regulations. The required water demand of the irrigation systems and their corresponding pressure heads were also determined. The electricity demand of the system was calculated, and the PV system was designed for an optimal irrigation system. Additionally, an economical assessment was made for two years. In the first year, the cost effectiveness of energy-efficient actions was evaluated for the irrigation system, and it was found that they had paybacks of approximately two years. In the second year, the implementation of a PV system in each demonstrative unit was evaluated. The on-grid solar PV system performed better than the off-grid system, with evaluated paybacks of approximately 12 years. Finally, some recommendations for a well-designed on-grid solar PV system were made on the basis of it lasting over 25 years, with an adequate operation and maintenance plan

NITROGEN, PHOSPHORUS AND POTASSIUM CONTENT IN DIFFERENT ORGANS OF PINEAPPLE CULTIVARS AT DIFFERENT PLANTING DENSITY

Background. The amount of nutrients required by pineapple varies depending on the cultivar and planting density. Knowing the nutrient requirement in quantity and the appropriate phenological stage will allow the development of an adequate fertilization program. Objective. To determine the effect of pineapple cultivar and planting density on N, P, and K content during plant development and at harvest. Methodology. The cultivars 'Smooth Cayenne', 'Champaka', and 'MD-2' were established at 30000, 45000, and 60000 plants ha-1. Eight samples were taken to determine the N, P, and K content in the organs and the total plant. Results. The highest and lowest N, P, and K contents were detected in the leaf and root, respectively. The highest N and K contents occurred at 441 - 506 days after planting. Higher P content occurred close to harvest. The highest N, P, and K contents per plant were at 30000 plants ha-1 (14.86, 1.52, and 16.29 g plant-1, respectively) and the lowest at 60000 plants ha-1 (10.16, 1.13, and 14.6 g plant-1, respectively). Higher N, P, and K contents per hectare were detected with 60000 plants ha-1 (609, 68, and 875 kg ha-1, respectively).  At harvest, ‘Smooth Cayenne’ at 60000 plants ha-1 accumulated the highest amount of N, P, and K (147, 37, and 306 kg ha-1, respectively). Implications. The changes that can occur in the nutrient requirements of pineapple as a function of cultivar, planting density, and stage of plant development were identified. This information will be useful for producers, agricultural technicians, and researchers in Mexico and the world, to generate fertilization programs or establish new research. Conclusion. At the beginning of plant growth, a higher N, P, and K contents in the leaf, this amount decreases as the fruit harvest approaches. Regardless of cultivar, the highest nutrient content per plant occurs at the lowest planting density, however, the highest content per hectare occurs at the highest planting density. At harvest time, fewer nutrients are removed from the soil with 'Champaka' and 'MD-2' fruit