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Search Results: 1 - 10 of 464128 matches for " Lourdes; Zavaleta-Mejía "
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Alternativas de control en la pudrición radical de cebolla para el Valle de la Trinidad, Baja California
Pulido-Herrera, Armando;Zavaleta-Mejía, Emma;Cervantes-Díaz, Lourdes;Grimaldo-Juárez, Onécimo;
Revista mexicana de ciencias agrícolas , 2012,
Abstract: onion's root rot is the most important disease in the trinidad valle, baja california, mexico. in orderto evaluate strategies to control this disease, three experiments were conducted during 2007, 2008 and 2009. in experiment i (2007) the treatments were: 1) thiophanate methyl; 2) smicobac (trichoderma+bacillus sp. + azospirillum sp. + pseudomonas sp.); 3) cattle manure (eb); 4) waste of onion (rc); 5) clear plastic solarization (spt); 6) black plastic solarization (spn); 7) spt + eb; 8) spt + cr; 9) spn + eb; 10) spn + so; 11) trichodef (trichoderma harzianum); and 12) control. in experiment ii (2008), treatments were the same except treatment 2, replaced by a protective agent (plant extracts), and in experiment iii (2009) the treatments were: 1) spt + sheep manure (eo); 2 ) spn + eo; 3) spt; 4) spn; 5) biological control (trichoderma spp.); and 6) chemical control (2 - (thiocyanomethylthio) benzothiazole 30%. the results indicated that the clear plastic solarization treatments with or without organic amendments showed significant increases (p<0.05) from 22 to 34%yield and diameterwith respect to biological and chemical control, but the latter two treatments in the incidence and severity decreasedsignificantly (p<0.05 ), so that the clearplastic solarization and biological control, are viable alternatives to control root rot in onion crops in baja california, mexico.
Alternativas de control en la pudrición radical de cebolla para el Valle de la Trinidad, Baja California Control Alternatives for Onion root rot in the Trinity Valley, Baja California
Armando Pulido-Herrera,Emma Zavaleta-Mejía,Lourdes Cervantes-Díaz,Onécimo Grimaldo-Juárez
Revista mexicana de ciencias agrícolas , 2012,
Abstract: La pudrición radical en cebolla es la enfermedad más importante en el Valle de la Trinidad, Baja California, México. Con el propósito de evaluar estrategias de control para la enfermedad se realizaron tres experimentos durante 2007, 2008 y 2009. En el experimento I (2007) los tratamientos fueron: 1) Tiofanato metílico; 2) Smicobac (Trichoderma + Bacillus sp. + Azospirillum sp. + Pseudomonas sp.); 3) estiércol de bovino (EB); 4) residuos de cebolla (RC); 5) solarización plástico transparente (SPT), 6) solarización plástico negro (SPN); 7) SPT + EB; 8) SPT + RC; 9) SPN + EB; 10) SPN + RC; 11) Trichodef (Trichoderma harzianum);y 12)testigo. En el experimento II (2008), los tratamientos fueron los mismos excepto el tratamiento 2, sustituido porprotector (extractos vegetales); y en el experimento III (2009) los tratamientos fueron: 1) SPT + estiércol de ovino (EO); 2) SPN + EO; 3) SPT; 4) SPN; 5) control biológico (Trichoderma spp.); y 6) control químico (2- (tiocianometiltio) benzotiazol 30%. Los resultados indicaron que los tratamientos solarización plástico transparente con o sin enmiendas orgánicas, presentaron incrementos significativos (p≤ 0.05) de 22 a 34% en el rendimiento y diámetro del bulbo con respecto al control biológico y químico; sin embargo, en estos dos últimos tratamientos la incidencia y severidad se redujo significativamente (p≤ 0.05), por lo que la solarización con plástico transparente y el control biológico, son alternativas viables para el control de la pudrición radical en cultivos de cebolla en Baja California, México. Onion's root rot is the most important disease in the Trinidad Valle, Baja California, Mexico. In orderto evaluate strategies to control this disease, three experiments were conducted during 2007, 2008 and 2009. In experiment I (2007) the treatments were: 1) Thiophanate methyl; 2) Smicobac (Trichoderma+Bacillus sp. + Azospirillum sp. + Pseudomonas sp.); 3) cattle manure (EB); 4) waste of onion (RC); 5) clear plastic solarization (SPT); 6) black plastic solarization (SPN); 7) SPT + EB; 8) SPT + CR; 9) SPN + EB; 10) SPN + SO; 11) Trichodef (Trichoderma harzianum); and 12) control. In Experiment II (2008), treatments were the same except treatment 2, replaced by a protective agent (plant extracts), and in experiment III (2009) the treatments were: 1) SPT + sheep manure (EO); 2 ) SPN + EO; 3) SPT; 4) SPN; 5) biological control (Trichoderma spp.); and 6) chemical control (2 - (thiocyanomethylthio) benzothiazole 30%. the results indicated that the clear plastic solarization treatments with or without organic amendments sho
Detección de geminivirus asociados a la alstroemeria (alstroemeria l.) En villa guerrero, estado de México
Cervantes-Díaz,Lourdes; Zavaleta-Mejía,Emma; Rojas-Martínez,Reina Isabel; Alanís-Martínez,Iobana; Ochoa-Martínez,Daniel Leobardo; Valadez-Moctezuma,Ernestina; Grimaldo-Juárez,Onécimo;
Interciencia , 2009,
Abstract: in alstroemeria (alstroemeria l.) plantations located in villa guerrero, mexico state, plants with symptoms similar to those induced by geminivirus in other horticultural crops have been detected. in addition, the presence of whiteflies, which are considered the most efficient vectors of these viruses, has been observed in these plantations. the goal of this work was to detect the presence of this geminivirus species in alstroemeria plants. by means of pcr analysis using primers motcp2118/motcp2123, a fragment of ~600pb similar to the amplicon obtained from phyvv-infected positive control was amplified only from symptomatic plants. nicotiana glutinosa, n. benthamiana, n. rustica, n. tabacum var. xanthi and datura stramonium plants were inoculated by bombardment with total dna obtained from symptomatic alstroemerias and positive to phyvv by means of pcr. inoculated plants showed mild mosaics and deformation of leaves, whereas in the leaves of capsicum annum plants, mosaics, vein necrosis and blisters were observed. using dna from these plants as template in pcr, amplicons corresponded to phyvv were also obtained; however, in bombarded monocotyledons, including alstroemeria, this fragment was not detected. the sequence of oligonucleotides from the pcr products showed 98% homology to phyvv geminivirus. even though symptoms presented by alstroemeria plants in the field were not reproduced, the presence of a geminivirus similar to phyvv in tissue of symptomatic plants was evidenced through pcr.
Interacción de componentes de resistencia e inóculo en trigo (Triticum aestivum L.) con tizón foliar (Septoria tritici Rog. Ex. Desm.)
Leyva-Mir, Gerardo;Gilchrist-Saavedra, Lucy;Zavaleta-Mejía, Emma;Khairallah, Mireille;
Agrociencia , 2008,
Abstract: the objective of the present study was to determine the effect of the inoculations of isolates of septoria tritici rob. ex. desm. individually and in mixtures, in the latent period, number of pycnidia and severity of the disease in seedlings in the latent period and later in doughy stage in nine genotypes of bread wheat (triticum aestivum l.) with different degree of resistance to the pathogen in atizapán, méxico, during two cycles. inoculation was made under field conditions with three individual isolates (p8, p9 and b1) and mixtures in nine wheat genotypes with different behavior to septoria tritici. the latent period in the susceptible cultivars was shorter and there was a higher number of pycnidia per surface unit, and the severity of the disease was greater with respect to the resistant genotypes. inoculation of two genotypes reduced the latent period and was lengthened in only two resistant genotypes. in contrast, the inoculation with the mixture of the three isolates always delayed the appearance of pycnidia in all of the susceptible cultivars and in four resistant ones of the six cultivars inoculated. regarding to the density of pycnidia per foliar area, the inoculation with two or three isolates resulted in significant reductions (p<0.05) of the number of pycnidia, with respect to the inoculations with individual isolates in the susceptible wheat, but not in the resistant wheat. the susceptible genotypes presented the greatest severity of the disease. a rapid formation of pycnidia was observed along with a higher number per surface unit. in concordance with the results of the latent period and density of pycnidia, the inoculation with mixtures of two and three isolates reduced the severity in the susceptible genotypes. however, in the resistant materials, the inoculations with mixtures did not always significantly reduce severity. in resistant and susceptible materials, the inoculation with mixture of two isolates caused a delay in the latent period. it can
Presencia de fitoplasmas en papayo (Carica papaya) en México
Rojas-Martínez, Reyna I.;Zavaleta-Mejía, Emma;Rivas-Valencia, Patricia;
Revista Chapingo. Serie horticultura , 2011,
Abstract: tissue samples of papayo plants with mosaic and yellow crinkle symptoms collected from michoacan and veracruz were examined to detect phytoplasma with polymerase chain reaction (pcr), using primers derived from ribosomal rna 16s and 23s from phytoplasmas. the sequences of the amplified pcr products were homologous to polynucleotide sequences belonging to phytoplasmas. the restriction patterns obtained through digestion of the amplified dna evidenced the presence of two phytoplasmas in plants showing mosaic and yellow crinkle symptoms. one of them matched the aster yellow group 1 16s subgroup c. the patterns of the other phytoplasmas did not match any of the restriction patterns up to now reported. tissue from diseased plants reacted positively to the fluororochrome-4,6-dyamidino-2- phenylindol (dapi) which stains dna, therefore suggesting the presence of nucleic acids from biotic agents inside the phloem.
Virulence and Genetic Variation of Isolates of Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. on Mango (Mangifera indica L.) cv. Haden
Rojas-Martínez, Reyna Isabel;Zavaleta-Mejía, Emma;Nieto-ángel, Daniel;Acosta-Ramos, Marcelo;
Revista mexicana de fitopatología , 2008,
Abstract: the virulence and genetic variation shown by rapd (random amplified polymorphic dna) were determined for 15 monoconidial isolates of colletotrichum gloeosporioides obtained from leaves and fruits of mango (mangifera indica) cv. haden. they were classified into four groups according to their degree of virulence onto inoculated leaves: very virulent (from 19.2 to 9.0% severity, isolates f3, f4, and t5), virulent (from 8.0 to 5.0%, t4, t3, f5, and t1), moderately virulent (from 3.8 to 1.2%, h4, h2, t6, f2, and h3), and scarcely virulent (from 0.1 to 0.01%, h1, f1, and t2). f3 was the most virulent as it showed the highest anthracnose severity. isolates h4, h1, h2, h3, t6, f2, and t2, showed greater genetic variability and were part of a group that was well separated from f3, f4, and f5. these three were outside the main groups in the dendrogram that was constructed from results of the rapd analysis. t5 (very virulent) was associated with t3 and t4 (virulent); however, f1 (scarcely virulent) was grouped with f5 (virulent). the results from the rapd analysis suggest the existence of great genetic variability among the 15 isolates of c. gloeosporioides.
Virus associated with thickening of the cladodes of prickly pear (Opuntia ficus-indica Mill.)
Alba Suaste-Dzul,Reyna Isabel Rojas-Martínez,Daniel Ochoa-Martínez,Emma Zavaleta-Mejía
Journal of Biotechnology and Biodiversity , 2012,
Abstract: Symptoms putative to phytoplasmas and virus as yellowing, mosaic, proliferation and deformation of fruits andthickening of the cladodes of prickly pear have been observed in Nopaltepec, Estado de México. The objective ofthis investigation was to detect the presence of virus in samples of prickly pear showing thickening syndrome of thecladodes. The analysis of double-stranded RNA in prickly pear tissue whit the symptoms mentioned above revealedthe presence of viral RNA. In symptomatic tissue, flexible rods of 950-1700 nm in length were observed with the aidof transmission electron microscopy. The virus was transmitted mechanically to Nicotiana tabacum var. Xanthi, N.glutinosa, N. occidentalis, N. benthamiana, Chenopodium quinoa, C. amaranticolor and Datura stramonium.Results from RT-PCR indicate that the particle does not correspond to TMV, neither to member of the Potyviridaefamily or species of the genus Potexvirus.
Identificación de un aislamiento del grupo 16SrIII, Candidatus Phytoplasma pruni en plantas y semillas de amaranto (Amaranthus hypochondriacus L.) en México
Rojas-Martínez, Reyna I.;Zavaleta-Mejía, Emma;Lee, Ing-Ming;Aragón-García, Agustín;
Agrociencia , 2009,
Abstract: recently in the state of tlaxcala, méxico, the "witches' broom syndrome" (proliferation of shoots and reduction of internodes) was observed in amaranth (amaranthus hypochondriacus l.). this symptomatology in the field is uniformly distributed in the plantation rather than randomly or in patches, and the most severe damage is in the panicle which contains the seeds, generating considerable losses in the harvest. therefore, the objective of the present study was to determine the presence of phytoplasmas in plants with symptoms of witches' broom syndrome and in seeds from diseased plants. in all of the samples that were processed an associated phytoplasma was found pertaining to the group 16sr iii, according to the results of the comparison of the patterns generated with enzymes of restriction of the products amplified by pcr. the sequences of the products obtained presented similarity of 98 % with the phylogenic group 16sr iii candidatus phytoplasma pruni.
Análisis temporal de la pudrición blanca (Sclerotium cepivorum Berk.) de la cebolla (Allium cepa L.) bajo tres niveles de inóculo del patógeno
Ponce-Herrera, Víctor;García-Espinoza, Roberto;Rodríguez-Guzmán, Ma. del Pilar;Zavaleta-Mejía, Emma;
Agrociencia , 2008,
Abstract: temporal behavior of white rot disease, caused by the fungus sclerotium cepivorum, was assessed on three onion plots, located at rancho agua nueva, municipality of juventino rosas, guanajuato, méxico. the plots had different soil inoculum density (id) of the pathogen: 0.021, 0.052, and 0.44 sclerotia g-1 soil, classified as low, medium, and high. the first plants with symptoms were observed 30 d after transplanting (dat), and the last diseased plants were recorded 160 dat. at this time, accumulated disease incidence was 51.93, 67. 75, and 82.9%, corresponding to low, medium, and high id. the relationship between disease progress curves and crop phenology showed that at the highest soil id, maximum disease incidence (ymax) occurs at the earliest phenology stages. temporal progress of white rot at low and medium id (0.021 and 0.052 sclerotia g-1 soil) was described by gompertz growth model, while high id (0.44 sclerotia g"1 soil) was described by the monomolecular model. the comparison of epidemics was performed taking into account the growth rates homologized to the gompertz model (rho) and by the area under the disease progress curve (audpc) showing significant differences (p<0.01). initial id of s. cepivorum in soil determines important epidemiological characteristics like disease increase rate (r), form of disease progress curve, phenological stage of maximum incidence (ymax), and final disease incidence (yf ), useful for understanding and predicting disease development in field and taking decisions on disease management.
Incorporación de vermicomposta para el manejo de Nacobbus aberrans en jitomate (Lycopersicon esculentum Mill.)
Villa-Briones, A.;Zavaleta-Mejía, E.;Vargas-Hernández, M.;Gómez-Rodríguez, O.;Ramírez-Alarcón, S.;
Revista Chapingo. Serie horticultura , 2008,
Abstract: the effect of vermicompost and manure was tested for the management of nacobbus aberrans. under greenhouse conditions gall index of tomato (lycopersicon esculentum mill.) roots (gi) was reduced significantly (p≤0.05), by 27 and 40%, respectively, when vermicompost and manure were incorporated to soil, in comparison to the control with nematode and without amendments. they also increased significantly the root volume (rv) 13.1 and 14.7 more times, dry root weight (drw) 5.8 and 7 more times and dry shoot weight (dsw) 1.6 and 1.9 more times; furthermore root necrosis was reduced by 28.5 and 25%, respectively. in the field, 85 days after planting, only the variables gi, root necrosis and dsw showed significant differences among treatments; generally, plants grown in soil amended with vermicompost at 12.5 t·ha-1 (500 g·plant-1) and 7.5 t·ha-1 (300 g·plant-1) reduced gi and root necrosis, and increased dsw. the gi was significantly reduced, as compared to the control, by 29 and 28% with 7.5 and 12.5 t·ha-1 of vermicompost, respectively; similarly, they increased the dsw by 91.6 y 84.8%.
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