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Phakopsora pachyrhizi, the causal agent of soybean rust, reduces soybean yield by up to 90%. Therefore, the development of preventive disease control measures is needed. We measured the distribution of airborne P. pachyrhizi urediniospores from 18 September 2014 to 21 May 2015, and their contribution to soybean rust in the Altamira municipality of southern Tamaulipas, Mexico. Three experiments, each with a different sowing time (early, late, and very late), were performed using the cultivar ‘Huasteca 200’, and an additional experiment was conducted with volunteer soybean plants. Urediniospores were trapped at weekly intervals using slide traps placed at two heights and in four different wind directions. Disease incidence and severity were scored beginning 12 July 2014 in each of the three canopy sections, and environmental conditions were registered. Spore distribution was continuous, and only the second of the two spore distribution phases contributed to disease. Disease incidence varied from 30 to 100% in experiments, and severity was the lowest (30°C) during the first phase, as well as low relative humidity (

El agua para riego que se utiliza en la region de Texmelucan, Puebla, y zonas colindantes proviene, principalmente, del deshielo de los volcanes y de los pozos profundos, aunque alrededor de 350 productores emplean aguas residuales. Se evaluaron algunos parametros que inciden en la calidad fisico-quimica del agua cuando se utiliza con fines de riego (pH, CE, Ca 2+ , Mg 2+ , K + , PO 4 2- , SO 4 2- , CO 3 2- , HCO 3 - , Na + , B y Cl - ) mediante un muestreo aleatorio realizado en 28 puntos de diversos afluentes del rio Atoyac. Los resultados muestran que la CE oscilo entre 0 y 0.875 dS m -1 ; el 64.28% correspondio a aguas de baja salinidad y bajo contenido de sodio (clase C1S1), el 28.57% a aguas con salinidad media y bajo contenido de sodio (clase C2S1) y el 7.15% a aguas de salinidad alta y bajo contenido de sodio (clase C3S1). En promedio, el Ca (0.98 meq L -1 ) y Mg (1.11 meq L -1 ) estuvieron presentes en mayor concentracion, lo que modifico favorablemente los valores de la relacion de adsorcion de sodio (RAS). Los iones bicarbonato (HCO 3 - ) en el agua presentaron una media de 1.83 meq L -1 . La concentracion de Cl - , HCO 3 - , CO 3 -2 , B y SO 4 -2 no ha afectado a los cultivos establecidos y la concentracion de PO 42- es un aporte significativo a los cultivos. Estos resultados indican que la region de Texmelucan tiene agua apta para el riego desde el punto de vista fisico-quimico; sin considerar el contenido de metales pesados ni el resultado de los analisis biologicos de la misma.

En el cultivo de Agave tequilana, los estudios se han restringido a una parte de su largo ciclo y a periodos cortos de tiempo, por tal razón, con el objetivo de evaluar las características agronómicas en planta y piña en un ciclo completo de la planta, se establecieron hijuelos provenientes de Jalisco en el sur de Tamaulipas en tres condiciones: a) en temporal y sin fertilizante (TA); b) fertigación, además de la precipitación, recibieron agua y nutrimentos (N, P, K, Ca, Mg, y micronutrimentos) mediante un sistema de riego por goteo; y c) FB+fertigación, adicional a lo anterior, éstas plantas recibieron fertilización de base (FB), con N, P, K y micronutrimentos, cada tratamiento tuvo tres repeticiones. Se realizaron ocho evaluaciones destructivas utilizando una planta por unidad experimental, septiembre 2004, febrero del 2005, octubre de 2005, 2006, 2007, 2008, 2009 y 2010. Las plantas desarrolladas con fertigación y fb+fertigación, en promedio superaron en 26% y 57% la altura y número de hojas de plantas del TA, respectivamente; la mayor producción de Materia Seca (MS) anual fue 51.8 t ha-1, estimándose un total de biomasa por planta de 491.4 y 456.1 t ha-1 y 218.1 y 252.4 t ha-1 en la piña, respectivamente. En plantas del TA la biomasa total fue 97 t ha-1 y un rendimiento de piña de 46.5 t ha-1. En piña los azúcares evaluados en oBrix y azúcares reductores totales (ART) no fueron afectados por los tratamientos. La concentración de ART en la piña fluctuó entre 26.8 y 29%. La concentración de glucosa y fructosa fue similar en etapas iniciales de desarrollo de la piña; Sin embargo, al final del ciclo durante la etapa de máximo crecimiento el valor medio en la concentración de fructosa fue de 246.8 g por kg MS de piña y representó 88% de los dos monosacáridos solubles evaluados, la glucosa presentó un comportamiento inverso y representó el restante 12%.

Background. Vanilla wilt disease caused by Fusarium oxsyporum f. sp. vanillae is a major limitant factor in the vanilla crop production in México. Methodology. Temporal dynamics of vanilla wilt was studied under different crop production systems, rustic (RS), traditional (TS) and with orange tree as the tutor plant (OTS) in Papantla, Veracruz. Thirty vanilla plants per orchard were selected; roots and rhizosphere soil per plant were sampled from May to December of 2016, to assess Fusarium spp. incidence and severity in roots and inoculum density in rhizosphere soil. Plant phenology and weather variables were also estimated. Results. Temporal behavior of inoculum density and Fusarium spp. root incidence showed a monomolecular increase in all crop production systems. OTS showed the highest growth rates for ID (r = 0.023 propagules per day) and incidence (r = 0.006 % per day), but the lowest area under the disease progress curve (AUDPC) for severity (529.1 % per month), an intermediate amount for root biomass rate (r = 0.018 g per day) and the highest crop yield (0.6 t ha-1); meanwhile, RS obtained the highest disease severity AUDPC (1267.71 % per month), the lowest root biomass rate (r = 0.011 g per day) ) and zero crop yield. Disease severity in roots decreased their biomass and the crop yield. Greenhouse pathogenicity tests showed that Fusarium oxysporum induced similar wilt and rot disease symptoms in vanilla roots and stems, and foliar yellowing and fall, as those recorded in the crop field, but this not happened with Fusarium solani. Conclusion. Vanilla wilt disease occurred during the whole period of assessment in this study, and it was affected by the type of crop production system and management strategies.

Background. Vanilla wilt disease caused by Fusarium oxsyporum f. sp. vanillae is a major limitant factor in the vanilla crop production in México. Methodology. Temporal dynamics of vanilla wilt was studied under different crop production systems, rustic (RS), traditional (TS) and with orange tree as the tutor plant (OTS) in Papantla, Veracruz. Thirty vanilla plants per orchard were selected; roots and rhizosphere soil per plant were sampled from May to December of 2016, to assess Fusarium spp. incidence and severity in roots and inoculum density in rhizosphere soil. Plant phenology and weather variables were also estimated. Results. Temporal behavior of inoculum density and Fusarium spp. root incidence showed a monomolecular increase in all crop production systems. OTS showed the highest growth rates for ID (r = 0.023 propagules per day) and incidence (r = 0.006 % per day), but the lowest area under the disease progress curve (AUDPC) for severity (529.1 % per month), an intermediate amount for root biomass rate (r = 0.018 g per day) and the highest crop yield (0.6 t ha-1); meanwhile, RS obtained the highest disease severity AUDPC (1267.71 % per month), the lowest root biomass rate (r = 0.011 g per day) ) and zero crop yield. Disease severity in roots decreased their biomass and the crop yield. Greenhouse pathogenicity tests showed that Fusarium oxysporum induced similar wilt and rot disease symptoms in vanilla roots and stems, and foliar yellowing and fall, as those recorded in the crop field, but this not happened with Fusarium solani. Conclusion. Vanilla wilt disease occurred during the whole period of assessment in this study, and it was affected by the type of crop production system and management strategies.

The aim of this study was to identify the Colletotrichum species associated with anthracnose symptoms in coffee (Coffea arabica L.) plantations in northern Puebla, Mexico. In 2013, five surveys were conducted in different production areas and at different altitudes. Symptomatic leaves, shoots, and ripe and unripe fruits of the coffee variety Red Caturra were collected. Isolates were obtained and the Colletotrichum species were identified morphologically and characterized by multilocus sequence analyses of the ACT, CAL, GAPDH, and TUB2 genes and the rDNA region. Additionally, pathogenicity tests were conducted using six isolates. We identified C. gigasporum, C. gloeosporioides, C. karstii (two isolates), C. siamense, and C. theobromicola. This is the first report of these five species infecting leaves of coffee. The symptoms caused by these species were characterized, but the species causing Coffee Berry Disease was not found. This is the first report of a complex of species affecting coffee plants in the same geographical area in Mexico, and suggests that other complexes of species may be important pathogens in coffee-producing areas elsewhere.

La mancha foliar causada por Zymoseptoria tritici es una enfermedad que ocasiona pérdidas económicas importantes en las zonas trigueras del mundo. Cambios en las prácticas culturales como la labranza mínima, aunadas al uso irracional de fungicidas y a la gran plasticidad genética y capacidad reproductiva del hongo son responsables, en parte, del desarrollo de nuevas epifitias por esta enfermedad. Para su manejo se requiere de la implementación de diversas estrategias, como la rotación de cultivos y la remoción de residuos de cosecha; sin embargo, el uso de variedades resistentes es clave para incrementar la productividad del trigo (Triticum aestivum L.). México cuenta con algunas variedades comerciales de trigo harinero moderadamente resistentes. El objetivo de esta revisión fue conocer la situación actual de la mancha foliar, para identificar líneas futuras de investigación que coadyuven al manejo de la enfermedad en el país.

In regions of the State of Puebla (Mexico), gladiolus (Gladiolus grandiflorus Andrews) production has had asexual propagation problems, which have caused losses for producers, who mostly produce their own vegetative seeds. The aim of this study was to evaluate some physical qualities and health characteristics of corms and cormels generated at four fertilization rates (FD, kg ha-1): 65N-14.9P-171K-16.6Mg-31.2Ca-0.0B-0.0S (FD1); 40.5N-24P-171K-23Mg-37.2Ca-0.2B-8.5S (FD2); 81N-24P-171K-23Mg-37.2Ca-0.2B-0.0S (FD3); and 81N-24P-171K-23Mg-37.2Ca-0.0B-0.0S (FDR; traditional regional rate). Two hundred and forty corms, along with their cormels, of two varieties (’Borrega Roja’ and ’Espuma’) produced at four FDs were harvested. The following physical qualities of corms were assessed; corm fresh weight (CFW), number of cormels generated (NcMC), and total fresh weight (TFW); evaluated physical qualities of cormels were size (mm) and total weight. Cormel health was analyzed in 160 randomly disinfested pieces that were plated in agar medium with or without splitting. The percentage of identified fungus incidence was recorded. Data were analyzed by a non-parametric one-way ANOVA. No significant differences were shown for CFW. The best treatments were mainly FD2 followed by FD1. In relation to FD-R, FD2 in both varieties increased NcMC by 31% to 69%, TFW by 27% to 46%, 6-8 size by 24% to 27%, and the development of Fusarium oxysporum colonies was reduced by 100% in cormel internal tissue.

In Mexico in the region of Nopaltepec in Mexico State, the edible Cactus crop, Opuntia ficus-indica is mainly cultivated for prickly pear fruit production. This crop has problems with common pests (insects, mollusks and weeds) which may serve as reservoirs and together with the named Cactus with phytoplasma-like symptoms which through the time inhibit the fruit production, and for this reason, the farmers called these Opuntia plants as Planta Macho (male plant). For molecular identification of the probably involved phytoplasma during 2005 and 2006, 38 samples of Opuntia plant tissues, fruit and some pests were collected for DNA extraction. By direct and nested PCR, 16S rRNA gene was amplified and sequenced. PCR products were analyzed by RFLP with restriction enzymes and in the sequences restriction sites were mapped. Phylogenetic analysis showed that the same phytoplasma was associated with Opuntia crop and its pests (the weeds Argemone mexicana, a grass and Lupinus sp.; a chinch bugs, Chelinidea sp. and the brown garden snail, Helix aspersa). Thus the edible Cactus crop and pests represented novel hosts of Cactus male plant Phytoplasma, and was classified as 16SrI Aster yellows group, of the species Candidatus phytoplasma asteris. This is the first report of this phytoplasma in Mexico and elsewhere. Key words: Argemone, brown garden snail, chinch bugs, edible Cactus, grasses,Lupinus, male plant phytoplasma, Mexico.

Introduction . Mango producers of two important growing areas of the states of Guerrero and Michoacan, Mexico, reported extensive damage in mango trees caused by an abundant mycelial growth covering most diseased panicles of mango trees cv. Haden. Materials and methods . The fungus was isolated from panicles of mango. Pathogenicity was evaluated in the orchard by inoculating 20 inflorescences protected by cellophane paper bags. In vitro characterization was evaluated on monosporic cultures; conidial morphology and rate of growth were determined. A molecular characterization by DNA extraction was carried out to identify the microorganism. Results . Cladosporium tenuissimum caused necrosis of flowers, pedicels and small fruits on inoculated mango panicles cv. Haden in the long coast of Guerrero and Michoacan States of Mexico. The affected organs were covered with grey cottony mycelia and an olivaceous, green to grey sporulation. In vitro , young colonies were also olive green and velvety, turning dark green to grey with a whitish outer margin. The growth rate of colonies was 0.46 cm·day–1 . Conidia were subspherical, lime-shaped and fusiform, olivaceous in color with visible scars and denticle-like extensions. The mean size of conidia was (5.85 × 2.93) µm with variations of 3.2–23 µm × 1.98–5.47 µm. The molecular characteristics rendered C. tenuissimum after identification. Symptoms of inoculated or naturally infected tree organs were similar. A diagrammatic scale was developed for the evaluation of disease severity, which varied from 69% to 100% in infected panicles. The organs were susceptible from blooming to fruit set. Discussion . Further research is proposed to evaluate the geographical distribution of C. tenuissimum in the production areas of mango with the concomitant evaluations of strategies of control.

Existe poca información a nivel mundial sobre los hongos asociados al cultivo y semilla de amaranto, incluyendo a México, donde más del 50% de la superficie destinada a este cultivo se siembra con semilla de la cosecha anterior sin conocer su calidad sanitaria. En este estudio se identificaron morfológicamente y se caracterizaron molecularmente por PCR-ITS (polymerase chain reaction-internal transcribed spacer; por sus siglas en inglés) los hongos presentes en 17 muestras de semillas de Amaranthus hypochondriacus. Se identificaron 19 especies pertenecientes a 10 géneros: Aspergillus parasiticus, Cladosporium cladosporioides y Stachybotrys chartarum en semilla sin desinfectar superficialmente con hipoclorito de sodio; Alternaria alternata, Aspergillus flavus, A. niger, Fusarium equiseti, F. lateritium, F. oxysporum, F. sambucinum, F. solani, Penicillium simplicissimum, Phoma medicaginis y Rhizopus rhizopodiformis en semillas con y sin desinfección superficial; y Epicoccum nigrum, Trichoderma atroviride, T. hamatum, T. koningii y T. pseudokoningii en semilla desinfectada. Sus secuencias se depositaron en el banco de genes del NCBI. Se reporta por primera vez A. parasiticus, E. nigrum, tres especies de Fusarium, R. rhizopodiformis, S. chartarum, y tres especies de Trichoderma en semilla de A. hypochondriacus en México.

"Con el objetivo de identificar hongos patógenos en fruto de fresa y su relación con variedades y el sistema de cultivo, se hicieron cinco muestreos de postcosecha: tres en la región de Zamora, Michoacán, México, en diciembre del 2001, y en febrero y mayo del 2002, en las variedades Camarosa y Aromas, cultivadas con sistema tradicional, y con cubierta plástica. Los otros dos muestreos se realizaron en mayo del 2001 y 2002, en fruta importada de California, EUA. En cada muestra los frutos se clasificaron como sanos y sintomáticos, y se seleccionó una submuestra de 20 frutos. Los sanos se incubaron en cámara húmeda, y el tejido de los sintomáticos se sembró en medio de cultivo. Los hongos aislados se purificaron y se realizaron las pruebas de patogenicidad. Nueve hongos patógenos fueron identificados de la fruta nacional e importada: Aspergillus, Botrytis, Colletotrichum, Geotrichum, Mucor, Penicillium, Pestalotiopsis, Phytophthora, y Rhizopus stolonifer; y más de ocho hongos saprofíticos. Los de mayor frecuencia fueron Botrytis y R. stolonifer. No hubo relación entre variedades, ni el sistema de cultivo con el porcentaje total de aislamientos. Considerando la información publicada, Geotrichum sp. fue el único hongo no reportado en fresa de postcosecha; además, es el primer reporte de hongos y un pseudohongo de postcosecha de la fresa en México."