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EFECTO DE Trichoderma Harzianum EN EL CONTROL DE MILDIU (Pseudoperonospora Cubensis) EN PEPINO

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EFECTO DE Trichoderma Harzianum EN EL CONTROL DE MILDIU (Pseudoperonospora Cubensis) EN PEPINO Agronomía Costarricense 43(1): 101-111. ISSN:0377-9424 / 2019 www.mag.go.cr/rev agr/index.html www.cia.ucr.ac.cr Nota técnica EFECTO DE Trichoderma harzianum EN EL CONTROL DE MILDIU (Pseudoperonospora cubensis) EN PEPINO Allan Alvarado-Aguayo1/*, Wilmer Pilaloa-David*, Sinthya Torres-Sánchez**, Kevin Torres-Sánchez*** Palabras clave: Antagonismo; control biológico; enfermedades fungosas; hifa; micelio; mildiu. Keywords: Antagonistic; biological control; fungal diseases; hypha; mycelium; mildew. Recibido: 22/03/18 Aceptado: 08/06/18 RESUMEN ABSTRACT La investigación consistió en medir el Trichoderma harzianum effect on efecto de Trichoderma harzianum en el control mildew control (Pseudoperonospora cubensis) del mildiu (Pseudoperonospora cubensis) del in cucumber crops. This research measured pepino (Cucumis sativus L.). Se utilizó un diseño the effect of Trichoderma harzianum on mildew de bloques completos al azar (DBCA) con 5 tra- control (Pseudoperonospora cubensis) in tamientos y 4 repeticiones en el sector Vainillo cucumber crops (Cucumis sativus L.). A random del cantón El Triunfo, provincia del Guayas, complete block design (RCBD) relied on 5 Ecuador. Las variables analizadas fueron: el treatments and 4 repetitions was carried out in porcentaje de infección de mildiu, eficacia de los Vainillo of El Triunfo city, Guayas province, tratamientos, longitud del fruto (cm), diámetro de Ecuador. The variables analyzed were: infection fruto (cm), frutos por planta, rendimiento (kg por of mildew percentage, treatment efficiency, fruit planta) y análisis económico. Realizado el ensayo length (cm), fruit diameter (cm), fruit per plant se pudo constatar la presencia de la enfermedad ratio, yield (kg per plant) and economic analysis. del mildiu, obteniendo el mayor porcentaje de Once the test was carried out, the presence eficacia (84,4%) en el control con el tratamiento of mildew disease was verified, obtaining the de Benomyl 50 WP,- 400 g.ha-1 y el tratamiento highest percentage of efficacy (84.4%) in the de Tricho D.- 500 g.ha-1 con una eficacia de control of treatments with Benomyl 50 WP, - 400 84,24%. Mediante la relación beneficio-costo g.ha-1 and treatment with Tricho D - 500 g.ha-1 (RBC) obtuvieron los mejores resultados el trata- with 84.24% of efficacy. The best benefit cost miento de Benomyl 50 WP,- 400 g.ha-1 con una ratio was the treatment with Benomyl 50 WP, - RBC de 1,53 y el tratamiento de Tricho D.- 500 400 g.ha-1 with 1.53 and treatment Tricho D.- 500 g.ha-1 con una RBC 1,50. Se recomienda aplicar g.ha-1 with 1.50. It is recommended for the control T. harzianum en dosis de 500 g.ha-1para el con- of mildew in cucumber crops should apply T. trol del mildiu en el cultivo de pepino. harzianum in doses of 500 g.ha-1. 1 Autor para correspondencia. Correo electrónico: ** Universidad Agraria del Ecuador. Ciudad [email protected] Universitaria Milagro. Guayas, Ecuador. * Universidad Agraria del Ecuador. Programa *** Instituto Agro Ganadero La Troncal. Cañar, Ecuador. Regional de Enseñanza El Triunfo. Guayas, Ecuador. 102 AGRONOMÍA COSTARRICENSE INTRODUCCIÓN a fructificaciones del patógeno, esporangios y esporangioforos (Zitter y McGrath 2005). El pepino (Cucumis sativus L., familia El manejo de P. cubensis consiste en utili- Cucurbitaceae) es una planta herbácea anual zar variedades resistentes, permitir la circulación rastrera nativa de Asia y África, utilizada para la de aire entre plantas, aplicar fertilización adecuada alimentación humana desde hace unos 3000 años y controlar poblaciones de arvenses (Schultz y (Zopplo et al. 2008). En Ecuador los principales French-Monar 2011). Una estrategia para reducir mercados de destino para el pepino son Colom- pérdidas de producción es la aplicación de fungi- bia, Estados Unidos, Japón, Holanda, Puerto cidas protectantes como clorotalonil, oxicloruro Rico, Reino Unido, Bahamas y Bélgica (Tenemaza de cobre, zineb, mancozeb después de sembrar el y Sabando 2015). cultivo, y fungicidas curativos y antiesporulantes El cultivo es afectado por diversas enferme- (tebuconazole, iprovalicarb) al observar los prime- dades fungosas, las cuales se presentan cuando las ros síntomas de la enfermedad (Roa 2015). condiciones ambientales son propicias para su desa- En la actualidad se han utilizado diver- rrollo, sobre todo en cambios del estado vegetativo sos extractos vegetales para controles fitosanitarios a floración. Los hongos más comunes son Pythium, como alternativa a los agroquímicos. Por ejemplo Phytophthora, Rhizoctonia, Oidium, Colletotrichum, las saponinas, glucósidos oleosos, han sido evaluadas Fusarium y Pseudoperonospora (Arias 2007). para combate del mildiu en cucurbitáceas con bue- Para el manejo de las enfermedades fun- nos resultados en el control. Otros agentes biológicos gosas se debe planificar un programa que integre han sido ampliamente investigados, por ejemplo el todas las posibilidades de control orientadas a hongo micoparasítico Ampelomyces quisqualis y inhibir el desarrollo de los patógenos y dar un uso racional a los productos fitosanitarios. Ello por su capacidad para tolerar algunos fungicidas minimiza el impacto ambiental y económico, químicos, se han realizado aplicaciones combinadas además, de obtener productos inocuos en la cose- con buenos resultados (González et al. 2010). cha (FAO 2011). Los fungicidas, tanto sistémicos como El mildiu (Pseudoperonospora cubensis) protectores, presentan mayores posibilidades de es una de las enfermedades foliares más impor- crear resistencias por parte de los hongos, debido tantes del pepino en Ecuador, pues su desarrollo a sus mecanismos de acción muy específicos, es favorecido por las condiciones propicias de además, de dificultar la comercialización de la humedad que se mantienen durante periodos producción, ya que hay un tiempo de carencia que prolongados (Basantes 2015). Pertenece a la debe cumplirse entre la última aplicación y venta clase Oomycetes, orden Peronosporales, familia para consumo (Yañez et al. 2012). Peronosporaceae, que se caracteriza por su faci- Trichoderma (clase Sordariomycetes, lidad para sobrevivir en plantas silvestres de la orden Hypocreales, familia Hypocreaceae) es un familia cucurbitácea (Ruiz et al. 2008). El rocío hongo de gran importancia, a nivel agrícola, como de la noche favorece el desarrollo del mildiu y agente de control biológico frente a fitopatógenos durante el día cuando aumenta la temperatura, de importancia económica (Tovar 2008). Posee seca las hojas y favorece que las esporas sean cualidades antagónicas contra hongos del suelo, transportadas por el viento, los trabajadores y las principalmente de los géneros Phytophthora, Rhi- herramientas (Alonzo 2015). zoctonia, Sclerotium, Oidium y Fusarium, entre Los primeros síntomas inician en el haz otros. Trichoderma actúa como hiperparásito com- de las hojas en forma de manchas amarillentas petitivo que produce metabolitos anti fúngicos con formas irregulares. En condiciones de alta (Ezziyyani et al. 2004). Sus principales mecanis- humedad y en correspondencia con las manchas mos la antibiosis, micoparasitismo, competencia del haz, aparecen estructuras de color grisáceo- por nutrientes y espacio (Guigón y Muñoz 2013), oscuro en el envés, las cuales corresponden contiene metabolitos que inducen mecanismos de Agronomía Costarricense 43(1): 101-111. ISSN:0377-9424 / 2019 ALVARADO-AGUAYO et al.: Control de mildiu en pepino 103 resistencia en las plantas (Tovar 2008), y produce MATERIALES Y MÉTODOS toxinas y antibióticos (Romero et al. 2009). En Ecuador se ha estudiado Trichoderma harzianum El presente estudio se realizó en el sobre hongos en pepino, en condiciones de labo- sector El Vainillo (cantón El Triunfo, Guayas, ratorio e invernadero, en los que se observaron Ecuador), en las coordenadas UTM: Norte efectos positivos sobre la severidad de microorga- 9742000 / 9760400 y Este: 666800 / 694630 nismos patógenos (Vivas y Molina 2011). (IGM 2010). Se evaluaron 5 tratamientos y Hoy día es prioritaria una agricultura lim- 4 repeticiones, que resultan de 3 distintas pia, sin contaminantes y generadora de productos dosis de Trichoderma (producto comercial inocuos que contribuyan a la seguridad alimenta- Tricho-D) más 2 testigos, uno comercial y otro ria. El uso de Trichoderma como antagonista de absoluto, sobre el cultivo de pepino, variedad hongos es una alternativa al uso de fungicidas, Diamante F1. Se aplicaron 3 dosis de Tricho-D por lo que es preciso establecer las dosis de mayor y al testigo comercial Benomilo (Benomyl 50 eficacia en el control de mildiu para cucurbi- WP), a los 8 días después de la siembra, una táceas. El presente trabajo tiene como objetivo segunda aplicación a los 30 días y la tercera identificar el efecto favorable, desfavorable o nulo aplicación los 50 días (Cuadro 1) en un Diseño de la utilización de 3 dosis de Trichoderma para de Bloques Completos al Azar (DBCA) con 20 control de mildiu, y verificar las potencialidades parcelas experimentales en un área de 720 m2, de este hongo con medición de variables que con un distanciamiento de siembra de 0,8 m cuantifiquen el rendimiento del cultivo de pepino. entre hileras y 0,5 m entre plantas. Cuadro 1. Dosificaciones de los tratamientos para el control de mildiu en pepino. Tratamiento Descripción Dosis.ha-1 Días a la aplicación* 1 Tricho D (Trichoderma harzianum) 300 g.ha-1 8, 30 y 50 dds 2 Tricho D (Trichoderma harzianum) 400 g.ha-1 8, 30 y 50 dds 3 Tricho D (Trichoderma harzianum) 500 g.ha-1 8, 30 y 50 dds 4 Benomyl 50 WP, fungicida sistémico 0,4 kg.ha-1 8, 30 y 50 dds 5 Testigo absoluto sin aplicación -- No se aplica *dds=días después de la siembra. La valoración estadística de los datos se rea- Cuadro 2. Análisis de varianza. lizó mediante el análisis de varianza, al comparar las medias de tratamientos con la prueba de Tukey Fuente de variación GL al 5% de probabilidad (Montgomery 2000). El esquema de análisis de la varianza se explica en el Repeticiones 3 Cuadro 2, en donde se realizaron 4 tratamientos con Tratamientos 4 3 repeticiones cada uno, obteniéndose la cantidad de 12 parcelas de control donde fueron comparadas con EE 12 el testigo las medias en las diversas situaciones con el Total 19 fin de determinar el error experimental.
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