Biological efficacy against "Diaphorina citri" Kuwayama (Hemiptera: Psyllidae) of chemical compounds apllied to the soil and foliage in "Citrus latifolia" Tanaka

The citrus acreage of Mexico exceeds 532 000 hectares. This area is endangered by the recent detection of the bacterium Candidatus Liberibacter asiaticus in some states and by the wide distribution of the vector Diaphorina citri. The aim of this study was to evaluate the efficiency against D. citri of chemical compounds applied to the soil and foliage in Persian lime. Two field evaluations were made during 2011 with applications of spirotetramat and imidacloprid to foliage and soil, and of spinosad and avermectin only to foliage. In the first evaluation, the spirotetramat (400 mL/ha) and the imidacloprid (300 mL ha-1), applied to foliage, caused a decrease of nymphs of 78.8%-93.54% three days after the application. The Imidacloprid (300 mL ha-1), applied to the soil, the spinosad (0.1 L ha-1), and the avermectin (0.1 L ha-1), had 69.8%, 70.6% and 61.6% less nymphs than the control treatment. In the second evaluation, imidacloprid, applied to the foliage, decreased the population of nymphs in shoots by 81.9%.The lowest average of nymphs per shoot in various sampling dates was obtained with the spirotetramat and imidacloprid treatments applied to foliage; 89.6% and 87.5% less than the control, respectively. Of the products evaluated, the spirotetramat and the imidacloprid, when applied to foliage, exerted the greatest effect against D. citri.La superficie de cítricos en México es superior a 532 mil hectáreas. Esta área se encuentra en peligro por la reciente detección de la bacteria Candidatus Liberibacter asiaticus en algunos estados y por la amplia distribución del vector Diaphorina citri. El objetivo fue evaluar compuestos químicos aplicados al suelo y follaje contra D. citri en lima persa. Se hicieron dos evaluaciones en campo durante 2011. Con aplicaciones de espirotetramato e imidacloprid al follaje y al suelo y spinosad y avermectina sólo al follaje. En la primera evaluación, tres días después de la aplicación, el espirotetramato (400 mL/ha) e imidacloprid (300 mL ha-1) aplicados al follaje ejercieron una disminución de ninfas de 78.8% y 93.54%. El imidacloprid (300 mL ha-1) aplicado al suelo, spinosad (0.1 L ha-1) y avermectina (0.1 L ha-1), tuvieron 69.8%, 70.6% y 61.6% menos ninfas que el testigo. En la segunda evaluación, el imidacloprid aplicado al follaje disminuyó 81.9% la población de ninfas en brotes. El menor promedio de ninfas por brote en diversas fechas de muestreo se obtuvo con los tratamientos de espirotetramato e imidacloprid al follaje, 89.6% y 87.5% menos que el testigo, respectivamente. De los productos evaluados el imidacloprid y espirotetramato aplicados al follaje ejercieron mayor efecto contra D. citri

La Araña roja en yaca: bioecología y eficacia biológica de acaricidas

Jackfruit (Artocarpus heterophyllus) has become an important fruit and represents a production option for tropical areas of Mexico. However, due to its recent introduction, information on its associated pests and diseases and management recommendations is still limited. In 2017, deformation of the leaves, discoloration of the beam and the presence of spider webs on the underside caused by an unknown mite were observed. The objective of this research wasto identify the associated mite, determine its population distribution and fluctuation and evaluate the biological efficacy of acaricides. The study was conducted during 2018-2019 in Nayarit, Mexico. The identified mite is Tetranychus pacificusknown as the red spider. It is distributed in all producing areas of jackfruit in Nayarit. It was mainly detected from November to June with greater infestation in the Tecuitata producing area (0.86 mites’leaf-1) and Jalcocotan (0.57 mites’leaf-1) of the municipality of San Blas. On average in September and October its presence is imperceptible; however, in El Capomo only in July was detected which probably indicates an initial stage of dispersal of the mite. Significant correlation was observed (β= 0.0489, r= -0.73, F= 0.0345, α= 0.05) of the population with the temperature, with a decrease in the population at a higher temperature and accentuated from 26 ° C. No correlation was observed with relative humidity. The highest temperature (27.9 °C) and relative humidity (88.2%) occurred in the month of July and September, respectively, months in which the lowest mite population was observed. The acaricides evaluated exercised significant control. At 21 days after application, differences occurred between treatments and the absolute control (Pr>F= 0.0245). With the application of azadirachtin (1.9 g of iaL-1of water) and mineral oil (16.9 g of iaL-1of water) a control of 75.9% and 72.5%, respectively, was obtained.La yaca (Artocarpus heterophyllus) se ha convertido en un frutal importante y representa una opción de producción para zonas tropicales de México. No obstante, por su reciente introducción, la información sobre sus plagas y enfermedades asociadas y recomendaciones de manejo es aún limitada. En 2017 se observó deformación de hojas, decoloración del haz y presencia de telaraña en el envés causado por un ácaro desconocido. El objetivo de esta investigación fue identificar el ácaro asociado, determinar su distribución, fluctuación poblacional y evaluación de eficacia biológica de acaricidas. El estudio se realizó durante 2018-2019 en Nayarit, México. El ácaro identificado es Tetranychus pacificus conocido como araña roja. Se distribuye en todas las zonas productoras de yaca en Nayarit. Se detectó de noviembre a junio con mayor infestación en la zona productora de Tecuitata (0.86 ácaros hoja-1) y Jalcocotan (0.57 ácaros hoja-1) del municipio de San Blas. En promedio en septiembre y octubre es imperceptible su presencia; no obstante, en El Capomo sólo se detectó en julio lo que indica una etapa inicial de dispersión del ácaro. Se observó correlación significativa (β= 0.0489, r= -0.73, F= 0.0345, α= 0.05) de la población con la temperatura, con un decremento de la población a mayor temperatura y acentuándose a partir de los 26 °C. No se observó correlación con la humedad relativa. La mayor temperatura (27.9 °C) y humedad relativa (88.2%) ocurrieron en el mes de julio y septiembre, respectivamente, meses en los cuales se observó la menor población de ácaros. Los acaricidas evaluados ejercieron un control significativo. A los 21 días después de la aplicación ocurrieron diferencias entre tratamientos y el testigo absoluto (Pr>F= 0.0245). Con la aplicación de azadiractina (1.9 g de ia L-1 de agua) y aceite mineral (16.9 g de ia L-1 de agua) se obtuvo un control de 75.9% y 72.5%, respectivamente

Optimización de un protocolo para aislamiento de DNA de hojas de "Saccharum officinarum".

The DNA extraction free polysaccharides, polyphenols, plant protein and RNA is the initial step to several studies in molecular biology. There are various methods of extracting specific DNA of sugar cane (Saccharum officinarum), however, are time consuming and expensive equipment and reagents used. The aim of this study was to optimize a fast, efficient and inexpensive protocol for extracting DNA from leaves of S. officinarum. The variables evaluated were yield, purity, integrity and functionality of DNA purified from leaves of sugarcane 6 months old. Techniques spectrophotometry, agarose gel electrophoresis and molecular markers to evaluate the above variables were used. The performance variables (mg/g) and purity (A260:280 and A260:230) the extracted DNA showed highly significant differences (p˃ 0.05) protocol I. The best results were obtained with the protocol interaction I +N2, DNA yield 1.17 mg/g and 1.95 and 1.91 purities (A260:280 and A260:230). Functionality DNA by PCR amplification with the RAPD markers and TRAP bands sharp profiles generated good quality and easy to interpret. The use of the protocol I+N2 for extracting DNA from S. officinarum to obtain high yields of DNA with optimal quality and purity for applications of molecular markers is recommended.La extracción de DNA libre de polisacáridos, polifenoles, proteínas y RNA de plantas constituye el paso inicial para diversos estudios en Biología molecular. Existen diversos métodos de extracción de DNA específicos para caña de azúcar (Saccharum officinarum), sin embargo, consumen mucho tiempo y utilizan reactivos y equipos costosos. El objetivo del presente estudio fue optimizar un protocolo rápido, eficiente y de bajo costo para extraer DNA de hojas de S. officinarum. Las variables evaluadas fueron rendimiento, pureza, integridad y funcionalidad del DNA purificado de hojas de caña de azúcar de 6 meses de edad. Se utilizaron técnicas de espectrofotometría, electroforesis en geles de agarosa y marcadores moleculares para evaluar las variables anteriores. Las variables rendimiento (mg/g) y pureza (A260:280 y A260:230) del DNA extraído mostraron diferencias altamente significativas (p˃ 0.05) con el protocolo I. Los mejores resultados se obtuvieron con la interacción del protocolo I +N2, con un rendimiento de DNA de 1.17 mg/g y purezas de 1.95 y 1.91 (A260:280 y A260:230). La funcionalidad del DNA por amplificación por PCR con los marcadores RAPD y TRAP generaron perfiles de bandas nítidas de buena calidad y de fácil interpretación. Se recomienda el uso del protocolo I +N2 para la extracción de DNA de S. officinarum para obtener elevados rendimientos de DNA con calidad y pureza óptima para aplicaciones de marcadores moleculare

Current Situation and Perspectives of Fruit Annonaceae in Mexico: Biological and Agronomic Importance and Bioactive Properties

The Annonaceae family is one of the oldest angiosperms. The genus Annona is the one with the most species and, together with Asimina, the only ones that contain edible fruits. In the last 10 years, interest in these fruit species has increased, mainly due to their nutritional properties and their application in the treatment of human diseases. Mexico is the center of origin for most of them. However, at present much of the basic agronomic information, postharvest handling of the fruits, and their potential as new crops for areas with poor soils in organic matter or semi-dry climates is unknown. It is considered that these custard apple species may be an option to change towards instead of crops that have lost profitability and sustainability. A review of the current state of knowledge in different areas of the species A. muricata, A. macroprophyllata, A. reticulata, A. squamosa, and A. cherimola was carried out and to focus research efforts on the topics of greatest interest and on those where is required to achieve a sustainable production and use of these resources in Mexico. However, knowledge about the cultivation and potential uses of these species is needed to increase their commercialization; the integration of interdisciplinary and interinstitutional groups is required

Gene Expression Profile of Mexican Lime (Citrus aurantifolia) Trees in Response to Huanglongbing Disease caused by Candidatus Liberibacter asiaticus

Nowadays, Huanglongbing (HLB) disease, associated with Candidatus Liberibacter asiaticus (CLas), seriously affects citriculture worldwide, and no cure is currently available. Transcriptomic analysis of host–pathogen interaction is the first step to understand the molecular landscape of a disease. Previous works have reported the transcriptome profiling in response to HLB in different susceptible citrus species; however, similar studies in tolerant citrus species, including Mexican lime, are limited. In this work, we have obtained an RNA-seq-based differential expression profile of Mexican lime plants challenged against CLas infection, at both asymptomatic and symptomatic stages. Typical HLB-responsive differentially expressed genes (DEGs) are involved in photosynthesis, secondary metabolism, and phytohormone homeostasis. Enrichment of DEGs associated with biotic response showed that genes related to cell wall, secondary metabolism, transcription factors, signaling, and redox reactions could play a role in the tolerance of Mexican lime against CLas infection. Interestingly, despite some concordance observed between transcriptional responses of different tolerant citrus species, a subset of DEGs appeared to be species-specific. Our data highlights the importance of studying the host response during HLB disease using as model tolerant citrus species, in order to design new and opportune diagnostic and management methods