Huanglongbing disease (HLB), caused by Candidatus Liberibacter asiaticus (CLas), affects all commercial citrus species. Persian lime (Citrus latifolia Tanaka), a crop of global economic importance, has shown tolerance to this disease. Efforts are focused on extending the productive life of diseased trees through effective agronomic management. This study aimed to evaluate how different fertilization strategies influence the physiological and hormonal responses of Citrus latifolia on both healthy and HLB-affected plants. It compared the effects of low (Ma-1), medium (Ma-2), and high (Ma-3) doses of macronutrients, with and without the addition of micronutrients (Mi-1), using either soil (Mi-2) or foliar (Mi-3) applications. Treatments were applied every 18 days for one year. C. latifolia showed tolerance; however, HLB infection negatively affected growth parameters, photosynthetic activity, vascular bundle anatomy, reflectance at 550 and 790 nm, carbohydrate metabolism, and the concentration of salicylic acid and its biosynthetic precursors. The hormonal response showed higher levels of benzoic acid and lower levels of salicylic acid than those reported in susceptible citrus. Plants treated with low doses of macronutrients along with soil-applied micronutrients (Ma-1 + Mi-2) showed a 17.9% increase in growth, a 31.3% larger canopy volume, and an 83.3% reduction in starch accumulation compared to the treatment with high doses of macronutrients and both soil and foliar applied micronutrients (Ma-3 + Mi-3). These findings indicate that split soil fertilization with low-dose macronutrients and micronutrients might influence plant physiological responses, potentially improving disease management and decreasing fertilizer inputs.

Una de las estrategias para el manejo del Huanglongbing en México es disminuir las poblaciones del insecto vector Diaphorina citri Kuwayama mediante su manejo en áreas regionales de control (ARCOs) y reducir el riesgo de dispersión de Candidatus Liberibacter asiaticus. La resistencia a insecticidas y las prácticas inadecuadas al realizar su aplicación son factores que disminuyen su efectividad. Se estimó la presión de selección ejercida en las ARCOs de Martínez de la Torre, Veracruz, por insecticidas de diferentes grupos toxicológicos (GT) utilizados para el control de D. citri en aplicaciones regionales supervisadas (ARS) en 2013, 2014, y 2015, y en aplicaciones locales no supervisadas (ALNS) en 2015. Además, se determinaron los factores operacionales y ambientales con impacto en la efectividad del aceite parafínico de petróleo. En agosto 2015 se evaluó la efectividad biológica de clorpirifos + aceite parafínico en cuatro parcelas, y en marzo 2016 la aplicación sola de aceite parafínico en 20 parcelas. Los insecticidas pertenecientes a los GT aceites minerales, organofosforados heterocíclicos S-etil y espinosinas ejercieron la mayor presión de selección absoluta y relativa en las ARCOs evaluadas. La mortalidad promedio de ninfas de D. citri por la aplicación de clorpirifos + aceite parafínico (71%), fue mayor a la obtenida con la aplicación sola del aceite (39%). La dosis y velocidad aplicación fueron los factores que influyeron en la efectividad del aceite parafínico de petróleo. Among the strategies for Huanglongbing management in Mexico is the reduction of Diaphorina citri Kuwayama populations, the insect vector, through its management in regional control areas (RCA), and reducing the dispersion risk of Candidatus Liberibacter asiaticus. Resistance to insecticide and inadequate application practices are factors that may reduce their efficacy. Selection pressure exerted by several insecticides of different toxicological groups (TG) in the RCA of Martínez de la Torre, Mexico, used for the control of D. citri in supervised regional applications (SRA), were estimated in 2013, 2014, and 2015, and in 2015 in nonsupervised local applications. Also, the operational and environmental factors with impact on the effectiveness of paraffinic petroleum oil were determined. In August 2015, the effectiveness of chlorpyrifos + paraffinic oil in four orchards, and in March 2016, paraffinic oil sprayed alone in 20 orchards, were evaluated. Insecticides classified in the TG as mineral oils, heterocyclic S-ethyl organophosphates, and spinosines, exerted the greatest absolute and relative selection pressure in the evaluated RCA. Mean D. citri nymph mortality by the application of chlorpyrifos + paraffinic oil (71%) was higher than that of paraffinic oil (39%) alone. Dose and application speed were the factors influencing paraffinic oil effectiveness.

El objetivo de esta investigación fue generar una tipología de productores cafetaleros con base en variables de tipo social, cultural, económico y productivo para determinar las diferencias existentes entre ellos y ofrecer información a las instancias gubernamentales para que diseñen estrategias en pro del mejoramiento de la calidad de vida de los pobladores. Se aplicó una encuesta a 145 productores cafetaleros en 2014, en el Distrito 005 de Fortín, Veracruz. Los resultados mostraron que los productores se clasifican en tres tipos: de subsistencia, transicionales y empresariales. Los de tipo empresarial son los que poseen mayor nivel tecnológico, mayor superficie, mayor ingreso capitalizable, mayor número de cortadores con pago, en comparación con los de subsistencia y transicionales. Por su carácter tradicional, el cultivo del café en este Distrito ha representado una opción de subsistencia y reproducción, más que social o de acumulación de riquezas o de capital con alta productividad económica.

Background. The coffee production in Veracruz state is important in the economic, social, cultural, and environmental sectors, mainly for the small producers who are dedicated to this activity. However, this sector has different problems that have generated its stagnation or abandonment, some of these are caused by the effects of climate change, coupled with the inadequate management of coffee agroecosystems that favor deforestation, low biodiversity and the elimination of natural enemies of pest organisms. Objective. To assess the perception of small coffee producers about the relationship among flowering, pests and climate change in Sabanas, Veracruz. Methodology. Eleven producers were interviewed through a questionnaire with open questions that allowed them to state how they perceive coffee flowering, pest problems, climate change and how they relate to each other. Results. The main problems they mentioned are pests, drought, and delayed flowering. The main pests they mention are rust, nematodes, and the berry borer, and they also indicate the presence of the coffee stem borer, which they had not previously observed. Finally, they perceive that herbicides, deforestation and pollution negatively affect their agroecosystems. Implications. The work suggests carrying out monitoring in the study area and/or surrounding areas to know the dynamics and distribution of the pests present in the crop. Conclusion. Small producers relate the increase in severity and the occurrence of new pests with climate change. In addition, they observe that changes in temperature and precipitation influence the delay in flowering and generate certain stress in the plantations, which they consider it is aggravated by practices such as the application of herbicides and the removal of shade trees.