In vitro antagonistic activity of Trichoderma harzianum against Fusarium sudanense causing seedling Blight and seed rot on wheat

[EN] Fusarium sudanense is a novel fungus recently isolated from asymptomatic samples of wheat grains in Argentina. The fungus caused symptoms of seedling blight and seed rot on wheat after artificial inoculations. It is known that the production of mycotoxins by pathogens belonging to the Fusarium genus is harmful to human and animal health. Moreover, the warm and humid conditions that are favorable for growth and mycotoxin production of these species put the Argentinian wheat production area at a high risk of mycotoxin contamination with this novel pathogen. The aim of this work was to evaluate the antagonistic effect of Trichoderma harzianum against F. sudanense under in vitro tests at different environmental conditions. Fungi were screened in dual culture at different water activities (alpha(w)) (0.995, 0.98, 0.95, and 0.90) and temperatures (25 and 15 degrees C). The growth rate of the fungi, interaction types, and dominance index were evaluated. Also, the interaction between T. harzianum and F. sudanense was examined by light and cryo-scanning microscopy. T. harzianum suppressed the growth of F. sudanense at 0.995, 0.98, and 0.95 alpha(w) at 25 degrees C and 0.995 and 0.98 alpha(w) at 15 degrees C. Macroscopic study revealed different interaction types between F. sudanense and T. harzianum on dual culture. Dominance on contact where the colonies of T. harzianum overgrew the pathogen was the most common interaction type determined. The competitive capacity of T. harzianum was diminished by decreasing the temperature and alpha(w). At 0.95 alpha(w) and 15 degrees C, both fungi grew slowly, and interaction type "A" was assigned. Microscopic analysis from the interaction zone of dual cultures revealed an attachment of T. harzianum to the F. sudanense hyphae, penetration with or without formation of appressorium-like structures, coiling, plasmolysis, and a veil formation. According to our results, T. harzianum demonstrated capability to antagonize F. sudanense and could be a promising biocontrol agent.This work was supported by the Escuela Tecnica Superior de Ingenieria Agronomica y del Medio Natural (ETSIANM), UPV, Spain, and by Facultad de Ciencias Agrarias y Forestales of the Universidad Nacional de La Plata (grant no. 11A 296), Argentina.Larran, S.; Santamarina Siurana, MP.; Rosello Caselles, J.; Simón, MR.; Perelló, A. (2020). In vitro antagonistic activity of Trichoderma harzianum against Fusarium sudanense causing seedling Blight and seed rot on wheat. ACS Omega. 5(36):23276-23283. https://doi.org/10.1021/acsomega.0c03090S2327623283536Arnold, A. E. (2007). Understanding the diversity of foliar endophytic fungi: progress, challenges, and frontiers. Fungal Biology Reviews, 21(2-3), 51-66. doi:10.1016/j.fbr.2007.05.003Porras-Alfaro, A., & Bayman, P. (2011). Hidden Fungi, Emergent Properties: Endophytes and Microbiomes. Annual Review of Phytopathology, 49(1), 291-315. doi:10.1146/annurev-phyto-080508-081831Keswani, C., Singh, H. B., Hermosa, R., García-Estrada, C., Caradus, J., He, Y.-W., … Sansinenea, E. (2019). Antimicrobial secondary metabolites from agriculturally important fungi as next biocontrol agents. Applied Microbiology and Biotechnology, 103(23-24), 9287-9303. doi:10.1007/s00253-019-10209-2Mesa Vanegas, A. M., Calle Osorno, J., & Marín Pavas, D. A. (2020). Metabolitos secundarios en Trichoderma spp. y sus aplicaciones biotecnológicas agrícolas. Actualidades Biológicas, 41(111). doi:10.17533/udea.acbi.v41n111a02Moussa, T. A. A., Al-Zahrani, H. S., Kadasa, N. M. S., Ahmed, S. A., de Hoog, G. S., & Al-Hatmi, A. M. S. (2017). Two new species of the Fusarium fujikuroi species complex isolated from the natural environment. Antonie van Leeuwenhoek, 110(6), 819-832. doi:10.1007/s10482-017-0855-1Larran, S., Santamarina Siurana, M. P., Roselló Caselles, J., Simón, M. R., & Perelló, A. (2020). Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat. Journal of King Saud University - Science, 32(1), 468-474. doi:10.1016/j.jksus.2018.07.005Larran, S. Estudio de la micobiota endofítica asociada al trigo y soja y su significancia en la interacción con patógenos fúngicos; Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. 2016 http://sedici.unlp.edu.ar/handle/10915/54499.Shi, W., Tan, Y., Wang, S., Gardiner, D., De Saeger, S., Liao, Y., … Wu, A. (2016). Mycotoxigenic Potentials of Fusarium Species in Various Culture Matrices Revealed by Mycotoxin Profiling. Toxins, 9(1), 6. doi:10.3390/toxins9010006Bockus, W. W., Bowden, R. L., Hunger, R. M., Morrill, W. L., Murray, T. D., & Smiley, R. W. (Eds.). (2010). Compendium of Wheat Diseases and Pests, Third Edition. doi:10.1094/9780890546604Leslie, J. F., & Summerell, B. A. (Eds.). (2006). The Fusarium Laboratory Manual. doi:10.1002/9780470278376Perincherry, L., Lalak-Kańczugowska, J., & Stępień, Ł. (2019). Fusarium-Produced Mycotoxins in Plant-Pathogen Interactions. Toxins, 11(11), 664. doi:10.3390/toxins11110664Edwards, J., Auer, D., de Alwis, S.-K., Summerell, B., Aoki, T., Proctor, R. H., … O’Donnell, K. (2016). Fusarium agapanthi sp. nov., a novel bikaverin and fusarubin-producing leaf and stem spot pathogen of Agapanthus praecox (African lily) from Australia and Italy. Mycologia, 108(5), 981-992. doi:10.3852/15-333Andrade, J. F., & Satorre, E. H. (2015). Single and double crop systems in the Argentine Pampas: Environmental determinants of annual grain yield. Field Crops Research, 177, 137-147. doi:10.1016/j.fcr.2015.03.008Ortega, L. M., Dinolfo, M. I., Astoreca, A. L., Alberione, E. J., Stenglein, S. A., & Alconada, T. M. (2015). Molecular and mycotoxin characterization of Fusarium graminearum isolates obtained from wheat at a single field in Argentina. Mycological Progress, 15(1). doi:10.1007/s11557-015-1147-7Perelló, A. E., & Dal Bello, G. M. (2011). Suppression of tan spot and plant growth promotion of wheat by synthetic and biological inducers under field conditions. Annals of Applied Biology, 158(3), 267-274. doi:10.1111/j.1744-7348.2011.00460.xHarman, G. E., Petzoldt, R., Comis, A., & Chen, J. (2004). Interactions Between Trichoderma harzianum Strain T22 and Maize Inbred Line Mo17 and Effects of These Interactions on Diseases Caused by Pythium ultimum and Colletotrichum graminicola. Phytopathology®, 94(2), 147-153. doi:10.1094/phyto.2004.94.2.147Perelló, A., Lampugnani, G., Abramoff, C., Slusarenko, A., & Bello, G. D. (2016). Suppression of seed-borneAlternaria arborescensand growth enhancement of wheat with biorational fungicides. International Journal of Pest Management, 63(2), 157-165. doi:10.1080/09670874.2016.1252478Sempere, F., & Santamarina, M. P. (2009). Antagonistic interactions between fungal rice pathogenFusarium Verticillioides (Sacc.) Nirenberg andTrichoderma harzianum Rifai. Annals of Microbiology, 59(2), 259-266. doi:10.1007/bf03178326SAMAPUNDO, S., DEVLIEHGERE, F., DE MEULENAER, B., & DEBEVERE, J. (2005). Effect of Water Activity and Temperature on Growth and the Relationship between Fumonisin Production and the Radial Growth of Fusarium verticillioides and Fusarium proliferatum on Corn. Journal of Food Protection, 68(5), 1054-1059. doi:10.4315/0362-028x-68.5.1054Sempere Ferre, F., & Santamarina, M. P. (2010). Efficacy of Trichoderma harzianum in suppression of Fusarium culmorum. Annals of Microbiology, 60(2), 335-340. doi:10.1007/s13213-010-0047-yLlorens, A., Mateo, R., Hinojo, M. J., Valle-Algarra, F. M., & Jiménez, M. (2004). Influence of environmental factors on the biosynthesis of type B trichothecenes by isolates of Fusarium spp. from Spanish crops. International Journal of Food Microbiology, 94(1), 43-54. doi:10.1016/j.ijfoodmicro.2003.12.017Magan, N., & Medina, A. (2016). Integrating gene expression, ecology and mycotoxin production by Fusarium and Aspergillus species in relation to interacting environmental factors. World Mycotoxin Journal, 9(5), 673-684. doi:10.3920/wmj2016.2076Pilar Santamarina, M., & Roselló, J. (2006). Influence of temperature and water activity on the antagonism of Trichoderma harzianum to Verticillium and Rhizoctonia. Crop Protection, 25(10), 1130-1134. doi:10.1016/j.cropro.2006.02.006Prasad, R. D., Rangeshwaran, R., Hegde, S. V., & Anuroop, C. P. (2002). Effect of soil and seed application of Trichoderma harzianum on pigeonpea wilt caused by Fusarium udum under field conditions. Crop Protection, 21(4), 293-297. doi:10.1016/s0261-2194(01)00100-4Perello, A. E., Monaco, C. I., Moreno, M. V., Cordo, C. A., & Simon, M. R. (2006). The effect ofTrichoderma harzianumandT. koningiion the control of tan spot(Pyrenophora tritici-repentis) and leaf blotch (Mycosphaerella graminicola) of wheat under field conditions in Argentina. Biocontrol Science and Technology, 16(8), 803-813. doi:10.1080/09583150600700099Larran, S., Simón, M. R., Moreno, M. V., Siurana, M. P. S., & Perelló, A. (2016). Endophytes from wheat as biocontrol agents against tan spot disease. Biological Control, 92, 17-23. doi:10.1016/j.biocontrol.2015.09.002Nakkeeran, S., Renukadevi, P., & Aiyanathan, K. E. A. (2016). Exploring the Potential of Trichoderma for the Management of Seed and Soil-Borne Diseases of Crops. Integrated Pest Management of Tropical Vegetable Crops, 77-130. doi:10.1007/978-94-024-0924-6_4Magan, N., & Lacey, J. (1984). Effect of water activity, temperature and substrate on interactions between field and storage fungi. Transactions of the British Mycological Society, 82(1), 83-93. doi:10.1016/s0007-1536(84)80214-4Sinclair, J. B. (1991). Latent Infection of Soybean Plants and Seeds by Fungi. Plant Disease, 75(3), 220. doi:10.1094/pd-75-0220Verhoeff, K. (1974). Latent Infections by Fungi. Annual Review of Phytopathology, 12(1), 99-110. doi:10.1146/annurev.py.12.090174.000531Sempere, F., & Santamarina, M. P. (2011). Cryo-scanning electron microscopy and light microscopy for the study of fungi interactions. Microscopy Research and Technique, 74(3), 207-211. doi:10.1002/jemt.2089

Endophytic Trichoderma strains increase soya bean growth and promote charcoal rot control

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goid., is one of the world's most serious diseases because it reduces yield and seed quality. Nowadays, biological control is an environment-friendly option for controlling plant diseases. The goals of this study were to (i) test eight endophytic Trichoderma spp. strains as biocontrol agents against M. phaseolina and (ii) further investigate two selected strains showing good behaviour against the pathogen. Pathogen-antagonist interactions were studied in dual culture, and the morphological alterations of M. phaseolina mycelia in the interaction zone were examined by light microscopy. Trichoderma strains were applied to soya bean seeds by a seed coating technique. Their bioprotective effects were assessed by in vitro and in vivo assays to evaluate radicle length, the germination percentage and the presence of typical charcoal rot symptoms in seedlings. Two Trichoderma strains were selected and they were molecularly identified as T. harzianum species complex. Their antagonistic ability against M. phaseolina was evaluated under different water availability conditions. The mechanisms used by these two endophytic strains against the pathogen were evaluated by cryo-scanning electron microscopy. The results showed that all eight Trichoderma strains successfully performed biocontrol activity against M. phaseolina by reducing colony growth and causing morphological alterations in the mycelia of M. phaseolina. All endophytes improved seed germination and radicle length, and reduced typical symptoms and disease progression on seedlings. Water availability in the medium impacted on fungal growth. At 0.995 ɑw, all the fungi grew more and faster. At 0.95 ɑw M. phaseolina grew more than the Trichoderma strains, while the pathogen grew slightly more at 0.98 ɑw than the Trichoderma strains. However, both selected Trichoderma strains grew larger and faster than the pathogen at 0.995 ɑw. The mechanisms involved in pathogen control revealed by the light and cryo-scanning microscopy studies included competition for nutrients or space and direct mycoparasitism. All the endophytic Trichoderma strains were antagonistic against M. phaseolina, however our study allowed us to select two Trichoderma strains with good potential to be included for charcoal rot management.Fil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; ArgentinaFil: Simon, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Santamarina, María Pilar. Universidad Politécnica de Valencia; EspañaFil: Roselló Caselles, Josefa. Universidad Politécnica de Valencia; EspañaFil: Consolo, Verónica Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas. Centro de Estudios de Biodiversidad y Biotecnología; ArgentinaFil: Perello, Analia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentin

First report of Alternaria alternata causing black spot on pink lapacho (Handroanthus impetiginosus)

A severe leaf spot disease was observed on pink lapacho trees, Handroanthus impetiginosus for the first time in Buenos Aires province, Argentina during the autumn of 2013. The pathogen was identified as Alternaria alternata based on the morphological characteristics and sequence data from the internal transcribed spacer region of ribosomal DNA, and partial β-tubulin sequence. A pathogenicity test was performed and Koch’s postulates were confirmed by re-isolating the fungus from artificially inoculated leaves. This is the first report of Alternaria black spot of Handroanthus impetiginosus trees

Environmental factors affecting the release and dispersal of pycnidiospores and ascospores of Mycosphaerella graminicola

Leaf blotch of wheat, caused by Mycosphaerella graminicola is an important wheat disease that produces yield losses in different regions of the world. The objectives of this study were to examine the relative abundance of M.graminicola ascospores and conidia in a field environment throughout a period of two years and establish the relationship between their release and the climatic conditions. This inoculum posses a risk to crop production and may be important to the epidemiology of septoria diseases in the wheat producing areas of Argentina. The inoculum level of airborne spores was measured in Julio Hirschron Experimental Stattion at Los Hornos locality during October 1998 to September 1999 to September 2000. Spore traps were used to monitor both ascospores and pycnidiospores when the wheat crop was in the vegetative and debris states. Samples were taken weekly. Data of pycnidiospores in water, in petroleum jelly and ascospores in petroleum jelly wee recorded

Biofilm containing the Thymus serpyllum essential oil for rice and cherry tomato conservation

IntroductionFungal pathogens cause major yield losses in agriculture and reduce food quality and production worldwide.PurposeTo evaluate new safer alternatives to chemicals for disease management and preserve the shelf life of food, this research was conducted to: determine the chemical composition of the essential oils (EOs) of Thymus serpyllum and Thymus piperella chemotypes 1 and 2; investigate the antifungal potential of EOs in vitro against: Alternaria alternata, Bipolaris spicifera, Curvularia hawaiiensis, Fusarium oxysporum f. sp. lycopersici, Penicillium italicum, Botryotinia fuckeliana; evaluate a natural T. serpyllum extract biofilm to conserve rice grain and cherry tomatoes.MethodEOs were analyzed by GC-MS+GC-FID. EOs’ antifungal activity was evaluated by dissolving Thymus extracts in PDA. Petri dishes were inoculated with disks of each fungus and incubated at 25°C for 7 days.ResultsThe T. serpyllum EO displayed the best Mycelial Growth Inhibition. The antifungal effect of the T. serpyllum EO biofilm was evaluated on rice caryopsis. Disinfected grains were dipped in a conidial suspension of each fungus and sprayed with EO (300 and 600 μg/mL) prepared in Tween 20. Grains were stored. The percentage of infected grains was recorded for 30 days. The T. serpyllum EO effect on cherry tomato conservation was evaluated in vivo. Wounded fruit were immersed in the T. serpyllum EO (300 and 400 μg/mL) and inoculated with Fusarium oxysporum f. sp. lycopersici. Fruit were evaluated for 7 and 14 days. Chemical profiles thymol/carvacrol for T. serpyllum, carvacrol for T. piperella Tp1 and thymol for T. piperella Tp2 were defined. The three evaluated EOs reduced all the studied phytopathogens’ fungal growth. The T. serpyllum biofilm was effective with rice storage and against Fusarium oxysporum f. sp. lycopersici for extending the shelf life of tomatoes in warehouses and storing postharvest cherry tomatoes.ConclusionWe suggest applying these EOs as biofilms for safe food conservation to replace synthetic products

Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat

[EN] An endophytic fungus isolated from healthy wheat seeds cultivar Klein Yarará in Buenos Aires Province, Argentina, was initially identified as belonging to the Fusarium fujikuroi species complex based on morphological and cultural characteristics. The fungus role in pathogenicity was investigated by artificial inoculation of wheat seeds. Symptoms evaluated 7 and 14¿days after inoculation showed that the fungus was pathogenic on seed and seedlings causing symptoms as seed decay, seedling blight and seed rot. The fungus was re-isolated to fulfill Koch¿s Postulates and was identified as F. sudanense (strain LBEA 3100), a new species recorded in Argentina. The fungal identity was corroborated using molecular techniques by sequencing the ITS region, D1/D2 domains of the LSU gene and TEF-1 alpha region and by comparison with international databases. Ecophysiological studies of F. sudanense (LBEA 3100) performed at different water activities and temperatures showed faster growth rate at the highest water activity and 25¿°C. This is the first report of F. sudanense, isolated from healthy wheat seeds, causing typical symptoms of seedling blight and seed rot on wheat.This work was supported by Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, Buenos Aires Province, Argentina (grant number 11A 296) and by Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires Province, Argentina (grant number (PIP) 819/14).Larran, S.; Santamarina Siurana, MP.; Rosello Caselles, J.; Simón, MR.; Perelló, A. (2020). Fusarium sudanebse, endophytic fungus causing typical symptoms of seedling blinht and seed rot on wheat. Journal of King Saud University - Science. https://doi.org/10.1016/j.jksus.2018.07.005

Association between Septoria tritici Blotch, Plant Height, and Heading Date in Wheat

The relationship between resistance to Septoria tritici blotch with plant height and heading date has been in most cases attributed to genetic associations. More efficient selection for higher levels of quantitative resistance may result if the nature of the association between susceptibility with earliness and shortness can be determined. Genetic resistance to Septoria tritici blotch and its relationships with plant height and heading date were recorded in 50 Argentinean wheat (Triticum aestivum L.) cultivars in three environments (two in the field and one in the greenhouse) with one virulent isolate of Mycosphaerella graminicola (Fuckel) Schroeter, in Cohn (anamorph Septoria tritici Rob. ex Desm.). Furthermore, a set of 16 cultivars was tested with seven isolates of M. graminicola in the greenhouse at the adult stage. Cultivars varied greatly in resistance to the disease and plant material was identified with moderate to high levels of resistance to several isolates. The field and greenhouse experiments demonstrated no evidence of genetic associations between plant height, heading date, and resistance, indicating that selection of early and short lines with high levels of quantitative resistance is possible. The relationships between those traits were mainly caused by environmental and epidemiological factors, which indicates that management of cultivars should be optimized to minimize these associations

Nature and effect of Alternaria spp. complex from wheat grain on germination and disease transmission

Diseases caused by Alternaria sp. are among the most common diseases of crops throughout the world. Alternaria sp. is a common component of the flora of wheat seed. Although isolation of Alternaria sp. from wheat (Triticum aestivum) seed has been reported in Argentina, development of the Alternaria blight in plants from infected seeds has not been demonstrated experimentally. Seed transmission of strains belonging to Alternaria tenuissima, A. alternata, A. infectoria, A. triticina, A. chlamydospora and related genera like Embellisia and Ulocladium sp. on wheat were investigated in the Argentinean growing area, on wheat cultivars Klein Escorpión and Buck Poncho. A. tenuissima was the dominant fungus in black pointed kernels. Transmission of all 42 seed-borne members of Alternaria complex from seeds to seedlings artificially inoculated was detected by trays seedling symptoms test. Among the fungi tested most isolates of Alternaria, Embellisia sp. and Ulocladium sp. produced distinct seed rot and seedling infection symptoms. This confirmed the seed-borne nature of these fungi. In each wheat cultivar tested inoculated seeds appreciably reduced their germination. The emerging coleoptile is externally infected by hyphal growth from the infected pericarp. Typical disease symptoms on the seedlings were exhibited. Recovery of the fungi from asymptomatic coleoptiles was also possible. Transmission efficiency varies with wheat cultivar and ranges from 0 to 92%. These results suggest that infected seed and seed transmission represents a mode of primary source of infection from which these microorganisms can start epidemics to the wheat crop and for dispersal of fungal strains to new areas.Fil: Perello, Analia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; ArgentinaFil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentin

Maíz: Importancia, origen, sistemática, morfología y composición química

El maíz (Zea mays L.) es una planta C4 con una alta tasa de actividad fotosintética, teniendo el más alto potencial para la producción de carbohidratos por unidad de superficie por día. Fue el primer cereal sometido a rápidas e importantes transformaciones tecnológicas en su forma de cultivo, tal como ha sucedido con la aparición de los híbridos. El éxito en los avances tecnológicos del cultivo de maíz estimuló una revolución agrícola generalizada en muchas partes del mundo. Es el primer cereal en rendimiento de grano por hectárea y el segundo, después del trigo, en producción total. Es considerado de gran importancia económica a nivel mundial ya sea como alimento humano (uno de los granos alimenticios más antiguos que se conocen), como alimento para el ganado o como fuente de un gran número de productos industriales. En Argentina en los últimos cinco años se han producido, en promedio, 26,5 millones de toneladas (SIIA, 2015) en 4 millones de ha., en tanto que a nivel mundial la producción promedio para las mismas campañas fue de 900 millones de toneladas (Maizar, 2015).Fil: Golik, Silvina Ines. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Gerard, Guillermo Sebastián. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fleitas, María Constanza. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Golik, Silvina Ines. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentin

Maíz: Manejo de enfermedades

Las enfermedades que afectan al maíz pueden ocasionar importantes disminuciones en el rendimiento producidas por interferencias en los procesos que conducen a la generación y partición de biomasa del cultivo (Fig.5.1). Algunas de ellas pueden reducir el stand de plantas, tal es el caso de la “podredumbre de la semilla” y “tizón de plántula”, la “podredumbre de la raíz y base del tallo”, el “mal de Río Cuarto”. Otras interfieren en la intercepción de radiación del cultivo, por reducir la superficie fotosintética o reducen la eficiencia de uso de la radiación, como pueden ser la “roya”, el “tizón del maíz”, el “mal de Río Cuarto”, otras reducen el índice de cosecha, ya que interfieren en los procesos involucrados en la producción y llenado de granos, como puede ser el “carbón de la espiga” o la “podredumbre de la espiga” y otras afectan la calidad de los granos como puede ser la “podredumbre de la espiga”. En estudios realizados en los últimos años se ha registrado la presencia de enfermedades que se reiteran anualmente (endémicas) y otras patologías consideradas emergentes, que dependen de las condiciones ambientales, el manejo y el material genético utilizado (Couretot, 2009). El concepto de manejo integrado de las enfermedades (MIE) tiene como base la resistencia genética e implica una serie de prácticas culturales que expongan a la población del patógeno a condiciones subóptimas reduciendo la aplicación de plaguicidas y evitando que la enfermedad llegue al umbral de daño económico.Fil: Simon, Maria Rosa. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Fleitas, María Constanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentin