First Report of Colletotrichum gloeosporioides Causing Anthracnose of Tejocote (Crataegus gracilior) Fruits in Mexico

Crataegus, is a genus classified in family Rosaceae and includes several tree species commonly called Tejocote that are widely cultivated for their pome fruits in Mexico. During fall of 2014, 2015, and 2016, severe symptoms of anthracnose were observed on approx. 60% of tejocote (Crataegus gracilior) fruits in an orchard located in Tulancingo, Oaxaca, Mexico. Affected fruits showed sunken, prominent, dark brown to black necrotic lesions, and were exuding salmon spore masses. To isolate the fungus, small pieces from tissue adjacent to the lesions of 10 symptomatic fruits were excised and surface disinfested by immersion in a 1% sodium hypochlorite solution for 2 min, rinsed three times in sterile distilled water, placed in Petri plates containing potato dextrose agar (PDA), and incubated at 25ºC for 5 to 7 days in darkness. Mycelial plugs were excised from the edge of the actively growing fungal colony and aseptically transferred to fresh PDA medium and incubated at 25°C for 6 days. Five monoconidial cultures were obtained by transferring germinated spores to Petri plates with fresh PDA. One isolate was selected as representative for morphological and molecular identification. Colonies of pure cultures exhibited greyish-white aerial mycelium and abundant salmon-pink conidial masses. Conidia (n= 100) were subcylindrical, hyaline, straight, one-celled, with rounded ends, measuring 13.6 to 17.7 × 4.4 to 5.9 μm. Conidial appressoria were ovoid and brown to dark brown. Based on morphological characteristics, the fungus was identified within the Colletotrichum gloeosporioides species complex (Weir et al. 2012). The isolate was designated UACH-177 and deposited in the Culture Collection of Phytopathogenic Fungi at the Chapingo Autonomous University. For molecular identification, the ITS region (White et al. 1990), and fragments of (Apn2) (Rojas et al. 2010), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β-tubulin 2 (TUB2) genes (Weir et al. 2012) were amplified by PCR, and sequenced. The sequences were deposited in GenBank (Accessions numbers ITS:MG821312; Apn2:MG821310; GAPDH:MG821311; and TUB2:MG821313). A phylogenetic analysis using Bayesian inference and including published ITS, Apn2, GAPDH, and TUB2 data for C. gloeosporioides and other Colletotrichum species was performed. The phylogenetic analysis showed the sequences were grouped into the clade of C. gloeosporioides. To confirm the pathogenicity of the fungus, 20 tejocote fruits were surface disinfested by immersion in a 1% sodium hypochlorite solution for 1 min, washed three times with sterile distilled water and dried on sterilized filter paper. Inoculations were performed by deposition of 10 μl of a conidial suspension (106 spores ml-1) on the fruit surface. Ten fruit were mock inoculated with distilled water as a control. All fruits were kept in a moist chamber at 25°C for 10 days. Pathogenicity test was repeated twice. Disease symptoms were observed on all inoculated fruit after 7 days, whereas control fruit did not develop symptoms. Fungal colonies were re-isolated from all symptomatic fruits and were found to be morphologically identical to the original isolate inoculated on tejocote fruits, thus fulfilling Koch´s postulates. In Mexico, García-Alvarez (1976) reported Colletotrichum sp. on fruits of Crataegus mexicana, however, that report was not supported by morphological characterization nor pathogenicity tests. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose of Crataegus gracilior in Mexico and worldwide.Fil: Nieto López, Edgar Humberto. University of Nebraska; Estados UnidosFil: Everhart, Sydney. University of Nebraska; Estados UnidosFil: Ayala Escobar, Victoria. Colegio de Postgraduados; MéxicoFil: Camacho Tapia, Moises. Universidad Autónoma Chapingo; MéxicoFil: Bernardi Lima, Nelson. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Nieto Angel, Raúl. Universidad Autónoma Chapingo; MéxicoFil: Tovar Pedraza, Juan Manuel. Universidad Autónoma Chapingo; Méxic

Agronomic and phytosanitary characterization of tomato production in the Comiteca- Tojolabal Plateau

Objective: Agronomic and phytosanitary characterization of tomato production units of the Meseta Comiteca-Tojolabal, Chiapas. Design/methodology/approach: Seventy-six tomato fields were sampled and the same number of surveys were applied to their respective farmers regarding agronomic practices and phytosanitary status of the crop. Results: Tomatoes are grown in shade-houses, on plots that mostly do not exceed half a hectare. The most common practices are crop rotation, one tomato cycle per year, incorporation of previous crop residues, and fertilization every 5-8 days. For phytosanitary management, foliar sprays are commonly performed every 5-8 days. Sixty seven percent of producers pre-treat seedlings to prevent diseases and pests. Ninety five percent perform applications of bactericides and fungicides to the roots, during the first 45 days of the crop. The most important pests and diseases are the whitefly, thrips, Bactericera sp, late blight, virus diseases and wilts. The incidence of diseased plants due to root and vascular diseases ranges from zero to 38%. However, low values ​​were more frequent. The severity of wilting at the regional level is low, since 90 % of the evaluated plants did not present symptoms. Limitations on study/implications: This is the first work that describes agronomic and phytosanitary aspects of tomato cultivation in this region. More research is required with this approach; this work will be the basis for further studies. Findings/conclusions: Most of the tomato farms are less than 0.5 ha, with an intensive phytosanitary treatment with pesticides. In addition to chemical control, the cultural practices used may be contributing to a low incidence and severity of soil-borne diseases. The most important crop diseases are late blight and virosis.Objective: To characterize the agronomic and phytosanitary aspects of the tomato production units of the Comiteca-Tojolabal Plateau, Chiapas, Mexico.Design/Methodology/Approach: A random sampling of n=76 tomato fields was performed; agronomic practice surveys were applied to their respective farmers, and the phytosanitary status of each site was evaluated.Results: Tomatoes are grown in shade houses, in plots that mostly do not exceed 0.5 ha. The most common practices are crop rotation, one tomato cycle per year, incorporation of previous crop residues, and fertilization every 5-8 days. For phytosanitary management, foliar sprays are usually performed every 5-8 days. In order to prevent diseases and pests, 67% of producers pre-treat seedlings and 95% apply bactericides and fungicides to the roots during the first 45 days of the crop. The most important pests and diseases are whitefly, thrips, Bactericera sp., late blight, virosis, and wilt. The percentage of plants that suffer from root and vascular diseases ranges from 0-38%. However, low values were more frequent. The regional severity of wilting is low, since 90% of the plants evaluated did not present symptoms. Study Limitations/Implications: This is the first work to describe the agronomic and phytosanitary aspects of tomato cultivation in this region. Additional research with this approach is required and this work will be the basis for further studies.Findings/Conclusions: Most of the tomato farms have less than 0.5 ha and their farmers carry out intensive phytosanitary management with pesticides. In addition to chemical control, the cultural practices used may contribute to a low incidence and severity of soil-borne diseases. The most important crop diseases are late blight and virosis

Diversidad morfológica y fisiológica de cepas nativas de Trichoderma spp. en suelos cacaoteros de México

Objective: To study the morphological, microscopic and physiological diversity of native species of Trichoderma genus associated with soils with cocoa cultivation in Mexico. Design / methodology / approximation: Colonies of Trichoderma spp. were isolated and characterized morphologically, microscopically and physiologically. from soil samples from six sites with different agronomic management: Organic Management, Conventional and No Management. A multivariate analysis (Analysis of main components and Analysis of hierarchical conglomerates) was carried out based on eight morphological characters of the colonies: shape, mycelium texture, obverse color, reverse color, central halo, number of concentric rings, type of sporulation and sporulation capacity; three microscopic characters: conidia shape and length / width relation of conidia and phialides. Results: 30 strains with macroscopic characteristics of the genus Trichoderma were isolated and purified. The Principal Components Analysis showed that the first three components expressed 66.27% of the total variability in the 30 strains of Trichoderma spp., observing a wide distribution of the strains from the analysis of the evaluated characters. The analysis of hierarchical clusters determined eight groups divided into subgroups from the semiparcial correlation coefficient of 0.05. Limitations of the study / implications: Trichoderma species show intraspecific variation that change with respect to the environmental conditions of the environment where they grow. Findings / conclusions: The morphological, microscopic and physiological characterization shows a high variability expressed in different characters that demonstrate the high diversity and specificity of Trichoderma spp. in soils with cocoa cultivation in Mexico.Objetivo: Estudiar la diversidad morfológica, microscópica y fisiológica de especies nativas del género Trichoderma asociadas a suelos cacaoteros de México. Diseño/metodología/aproximación: Se aislaron y caracterizaron morfológica, microscópica y fisiológicamente, colonias de Trichoderma spp. a partir de muestras de suelo de seis sitios con diferente manejo agronómico: Manejo Orgánico, Convencional y Sin Manejo. Se realizó un análisis multivariado (Análisis de componentes principales y Análisis de conglomerados jerárquicos) a partir de ocho caracteres morfológicos de las colonias: forma, textura del micelio, color anverso, color reverso, halo central, número de anillos concéntricos, tipo de esporulación y capacidad de esporulación; tres caracteres microscópicos: forma de conidios y relación largo/ancho de conidios y fiálides. Resultados: Se aislaron y purificaron 30 cepas con características macroscópicas del género Trichoderma. El Análisis de Componentes Principales mostró que los primeros tres componentes expresaron el 66.27 % de la variabilidad total en las 30 cepas de Trichoderma spp., observando una amplia distribución de las cepas a partir del análisis de los caracteres evaluados. El análisis de conglomerados jerarquicos determinó ocho grupos divididos en subgrupos a partir del coeficiente de correlación semiparcial de 0.05. Limitaciones del estudio/implicaciones: Las especies de Trichoderma muestran variación intraespecífica que cambian con respecto a las condiciones ambientales del medio donde crecen. Hallazgos/conclusiones: La caracterización morfológica, microscópica y fisiológica, muestra una alta variabilidad expresada en diferentes caracteres que demuestran la alta diversidad y especificidad de las especies de Trichoderma spp. en suelos cacaoteros de México

Salinidad cuantitativa y cualitativa del sistema hidrográfico Santa María-Río Verde, México

La investigación se desarrolló en el sistema hidrográfico Santa María-Río Verde, con el objetivo de conocer la evolución y salinidad de las aguas de riego tanto cuantitativa, expresada como conductividad eléctrica, como cualitativa, calculada mediante la relación de adsorción de sodio y magnesio, para posteriormente predecir sus efectos sobre los suelos y cultivos. La investigación fue no experimental transversal descriptiva, con el muestreo a juicio en 69 estaciones, muestreadas desde el invierno de 2009, y primavera y otoño de 2010. Se determinaron 10 mediciones en cada muestra de agua: cationes, aniones, pH y conductividad eléctrica (CE). Se siguió el modelo basado en la alcalinidad para determinar la vía evolutiva que toman las aguas, y se comprobó con un experimento de reconcentración de sales por evaporación. Se calculó el índice de saturación (IS) y las modificaciones de la relación de adsorción de sodio (RAS); éstas fueron, RAS y RASaj El sistema hidrográfico Santa María-Río Verde, de acuerdo con la salinidad cuantitativa, se clasificó en su mayoría de ríos como alta y muy altamente salinas; la salinidad cualitativa más crítica fue la magnésica, en comparación con la sódica, a pesar de que la calcita precipitará. La evolución de las aguas fueron de sulfatadas cálcicas a sulfatadas magnésicas y sódicas. Existe la tendencia a que aumente la concentración y cambie la tipología de la salinidad de las aguas del sistema hidrográfico Santa MaríaRío Verde, afectando los suelos y cultivos

Anales del III Congreso Internacional de Vivienda y Ciudad "Debate en torno a la nueva agenda urbana"

Acta de congresoEl III Congreso Internacional de Vivienda y Ciudad “Debates en torno a la NUEVa Agenda Urbana”, ha sido una apuesta de alto compromiso por acercar los debates centrales y urgentes que tensionan el pleno ejercicio del derecho a la ciudad. Para ello las instituciones organizadoras (INVIHAB –Instituto de Investigación de Vivienda y Hábitat y MGyDH-Maestría en Gestión y Desarrollo Habitacional-1), hemos convidado un espacio que se concretó con potencia en un debate transdisciplinario. Convocó a intelectuales de prestigio internacional, investigadores, académicos y gestores estatales, y en una metodología de innovación articuló las voces académicas con las de las organizaciones sociales y/o barriales en el Foro de las Organizaciones Sociales que tuvo su espacio propio para dar voz a quienes están trabajando en los desafíos para garantizar los derechos a la vivienda y los bienes urbanos en nuestras ciudades del Siglo XXI

Evaluación de pudrición de mazorca de híbridos de maíz en valles altos

In 2010, the ear rot severity and yield of 21 commercial hybrids at two locations and sowing dates were assessed (Santa Lucía de Prías, Coatlinchán, Texcoco, Estado de Mexico and San Luis Huamantla, Tlaxcala). In order to measure the ear rot severity, a severity scale was used. Seed samples with different degrees of rot severity were analyzed to determine the species of Fusarium fungi. An analysis of variance and separation of means were performed to identify the outstanding hybrid in yield and with less severity. Significant differences (p< 0.001) were found for yield and severity in the two studied localities. In St. Lucía, the outstanding hybrids in both sowing dates were HGVC-2 and Prospecto 4, with an average yield of 10.36 and 10.28 t ha-1 respectively and weighted severity of 8.99 and 15.16% respectively. In San Luis Huamantla, the yield was significant (p< 0.0022), the hybrids that had the highest yield were HP-1, Prospecto 4 and H-52 (10.27, 10.07 and 9.93 t ha-1, respectively), regarding to calculate the severity of hybrid Prospect 1, showing a weighted severity of 13%. The Fusarium species associated with ear rot, isolated from seeds with different severity degrees, were: Fusarium verticilloides, F. subglutinans, F. proliferatum, F. oxysporum and Cephalosporium sp.En 2010, se evaluó la severidad de pudrición de mazorca y el rendimiento de 21 híbridos comerciales en dos localidades y fechas de siembra (Santa Lucía de Prías, Coatlinchán, Texcoco, Estado de México y San Luis Huamantla, Tlaxcala). Para medir la severidad de pudrición de mazorca, se utilizó una escala de severidad. Se analizaron muestras de semillas con diferente grado de severidad de pudrición, para determinar las especies de hongos del género Fusarium. Se realizó un análisis de varianza y separación de medias para identificar los híbridos sobresalientes en rendimiento y con menor severidad. Se encontraron diferencias significativas (p< 0.001), para rendimiento y severidad en las dos localidades estudiadas. En Santa Lucía los híbridos sobresalientes en ambas fechas de siembras fueron HGVC-2 y Prospecto 4, con un rendimiento promedio de 10.36 y 10.28 t ha-1, respectivamente y una severidad ponderada de 8.99 y 15.16%, respectivamente. En San Luis Huamantla, el rendimiento fue significativo (p< 0.0022), los híbridos que tuvieron el mayor rendimiento fueron HP-1, Prospecto 4 y H-52 (10.27, 10.07 y 9.93 ha-1, respectivamente), en cuanto a la severidad calculada el híbrido Prospecto 1, presentó una severidad ponderada de 13%. Las especies de Fusarium asociadas a la pudrición de mazorca, aisladas a partir de semillas con diferentes grados de severidad, fueron: Fusarium verticilloides, F. subglutinans, F. proliferatum, F. oxysporum y Cephalosporium sp

Rosellinia necatrix EN Rosa sp. Y SU EVALUACIÓN A SENSIBILIDAD DE FUNGICIDAS

"En el año 2006 el cultivo de rosa en los municipios de Tenancingo, Villa Guerrero y Coatepec Harinas cubrió una superficie de 415 ha, siendo importante su valor de producción equivalente a 688,722,450.00 pesos. Este cultivo presenta una pudrición blanc

First report of Cladosporium cladosporioides causing leaf spot on tomato in Mexico

During 2017, a severe leaf spot disease was observed in a tomato greenhouse in Texcoco, Estado de México, Mexico. Symptoms on leaves included yellow irregular lesions on adaxial surfaces, whereas intense grayish brown sporulation developed on the undersides of the lesions. Disease incidence was approximately 35%. The pathogen was isolated on PDA medium and colonies exhibited sparse aerial mycelium, olivaceous-brown to brown, with a velvety texture and sporulation profuse. Conidiophores were solitary, straight to slightly flexuous, olivaceous-brown, narrowly cylindrical to subcylindrical-oblong, occasionally once geniculate, unbranched or occasionally branched, and measuring 40–300 × 2.5–3.5 μm. Conidia were catenated, in long branched chains, olivaceous-brown, smooth. Intercalary conidia were limoniform or sometimes subcylindrical, aseptate, of 5–12.5 × 1.8–2.4 μm. Secondary ramoconidia were aseptate or occasionally 1-septate, ellipsoid, cylindrical-oblong, of 12–15 × 2.5–3.5 μm. Based on morphological features, the fungus was identified within the Cladosporium cladosporioides species complex (Bensch et al. 2012). An isolate was deposited in the Culture Collection of Phytopathogenic Fungi of the Chapingo Autonomous University as UACH293. For molecular identification, the ITS region and part of EF1-α gene were amplified by PCR and sequenced using the primer sets ITS5/ITS4 and EF1-728F/EF1-986R, respectively. The sequences were deposited in GenBank (Accession Nos. ITS:MH785190 and EF1-α:MH785189). A phylogenetic analysis using Bayesian inference and including published ITS and EF1-α sequence dataset for Cladosporium species was performed. The phylogenetic analysis resulted in a well-supported clade grouped with the type species of C. cladosporioides. To verify the pathogenicity of the fungus, inoculations were performed on 20 leaves of two-month-old tomato plants by spraying a conidial suspension (105 spores/ml). Five leaves were mock inoculated with distilled water as a control. Symptoms of leaf spots were produced 10 days after inoculation, whereas the control leaves remained healthy. Cladosporium cladosporioides has been reported associated with tomato in Brazil, China, and Malaysia (Farr and Rossman 2018). To our knowledge, this is the first report of leaf spot on tomato caused by Cladosporium cladosporioides in Mexico.Instituto de Patología VegetalFil: Robles Yerena, Leticia. Colegio de Postgraduados. Campus Montecillo. Fitopatología; MéxicoFil: Ayala Escobar, Victoria. Colegio de Postgraduados. Campus Montecillo. Fitopatología; MéxicoFil: Leyva Mir, Santos Gerardo. Universidad Autónoma Chapingo. Departamento de Parasitología Agrícola; MéxicoFil: Bernardi Lima, Nelson. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Camacho Tapia, Moisés. Universidad Autónoma Chapingo. Laboratorio Nacional de Investigación y Servicio Agroalimentario y Forestal; MéxicoFil: Tovar Pedraza, Juan Manuel. Centro de Investigación en Alimentación y Desarrollo, Coordinación Culiacán. Laboratorio de Fitopatología; Méxic

Hongos asociados a Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) en Tabasco, México

In the state of Tabasco, Mexico, the coffee berry borer Hypothenemus hampei, was reported for the first time in 2004. Since then it has become the main insect pest of coffee in this area. The aim of the present study was to document the mycobiota associated to H. hampei adults in coffee plantations of three localities of Tabasco: Teapa, Tacotalpa and Huimanguillo. Coffee berries infested with the coffee berry borer were collected from the field and adults of H. hampei were extracted. The fungi that grew on the Scolytinae cadavers were isolated and identified using taxonomic keys. Two isolates of each morphological species were molecularly identified. A total of 74 isolates was obtained from the cuticle of H. hampei. Of them, 52 presented morphological affinity with Fusarium solani, five with F. oxysporum, five with F. verticillioides, one with Geotrichum candidum and 11 with Beauveria bassiana. The DNA sequences showed similarity with sequences found in GenBank, with homologies of 99 % and 100 %, which coincided with each morphological species. The most abundant species was F. solani (70.2 %), followed by B. bassiana (14.8 %). The species F. verticillioides and F. oxysporum represented each one, at 6.7 %, respectively. The least abundant was G. candidum (1.3 %). The findings of the species F. verticillioides and G. candidum are new reports of micromycetes fungi associated with H. hampei. This study contributes to the knowledge of the diversity of fungi associated with H. hampei.En el estado de Tabasco, México, la broca del café Hypothenemus hampei, se registró por primera vez en 2004. Desde entonces se ha convertido en la principal limitante insectil de la producción de café. El objetivo del presente trabajo fue identificar la micobiota asociada a adultos de H. hampei, recolectados en plantaciones de café en tres municipios de Tabasco: Teapa, Tacotalpa y Huimanguillo. Se recolectaron cerezas infestadas con la broca y se extrajeron los adultos de H. hampei. Los hongos que crecieron sobre los cadáveres de este Scolytinae se aislaron e identificaron morfológicamente. Dos aislamientos de cada especie morfológica se identificaron molecularmente. Se obtuvo un total de 74 aislamientos de la cutícula de H. hampei, de los cuales, 52 presentaron afinidad morfológica con Fusarium solani, cinco con F. oxysporum, cinco con F. verticillioides, uno con Geotrichum candidum y 11 con Beauveria bassiana. Las secuencias de ADN mostraron similitud con secuencias del GenBank, con homologías de 99 y 100 %, las cuales coincidieron con cada especie morfológica. La especie más abundante fue F. solani (70,2 %), seguida de B. bassianna (14,8 %). Las especies F. verticillioides y F. oxysporum representaron cada una el 6,7 %. La menos abundante fue G. candidum (1,3 %). Los hallazgos de F. verticillioides y G. candidum son nuevos registros de hongos micromicetos asociados a H. hampei

Fungi associated with Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) in Tabasco, Mexico.

In the state of Tabasco, Mexico, the coffee berry borer Hypothenemus hampei, was reported for the first time in 2004. Since then it has become the main insect pest of coffee in this area. The aim of the present study was to document the mycobiota associated to H. hampei adults in coffee plantations of three localities of Tabasco: Teapa, Tacotalpa and Huimanguillo. Coffee berries infested with the coffee berry borer were collected from the field and adults of H. hampei were extracted. The fungi that grew on the Scolytinae cadavers were isolated and identified using taxonomic keys. Two isolates of each morphological species were molecularly identified. A total of 74 isolates was obtained from the cuticle of H. hampei. Of them, 52 presented morphological affinity with Fusarium solani, five with F. oxysporum, five with F. verticillioides, one with Geotrichum candidum and 11 with Beauveria bassiana. The DNA sequences showed similarity with sequences found in GenBank, with homologies of 99 % and 100 %, which coincided with each morphological species. The most abundant species was F. solani (70.2 %), followed by B. bassiana (14.8 %). The species F. verticillioides and F. oxysporum represented each one, at 6.7 %, respectively. The least abundant was G. candidum (1.3 %). The findings of the species F. verticillioides and G. candidum are new reports of micromycetes fungi associated with H. hampei. This study contributes to the knowledge of the diversity of fungi associated with H. hampei