Biosolarización de invernaderos para cultivos de pimiento: manejo de patógenos y fatiga del suelo

[SPA] El cultivo de pimiento supone una parte importante de la economía agrícola de la Región de Murcia, en particular en la comarca del Campo de Cartagena donde ha llegado a ocupar unas 2000 ha de invernaderos. Las prácticas agrícolas de monocultivo han provocado una fuerte especificidad de importantes patógenos como Phytophthora spp., productora de la “tristeza del pimiento” y Meloidogyne incognita, que llegan a ser factores limitantes para este cultivo, por la importancia de las pérdidas que ocasionan. La prohibición del bromuro de metilo por su efecto nocivo en el medio ambiente, utilizado todos los años para desinfectar los suelos de los invernaderos del cultivo de pimiento, ha provocado una búsqueda incesante de alternativas que fueran sostenibles y duraderas. Para eso eran necesarios estudios actualizados de los patógenos principales y de las circunstancias actuales del cultivo, en particular sobre el causante de la muerte de plantas, sobre las características de la fatiga del suelo y sobre la biosolarización (biofumigación con solarización) como método de desinfección de los suelos. -Se ha realizado la caracterización del patógeno causante de la “marchitez o tristeza del pimiento” como paso previo al establecimiento de estrategias de control por medios no químicos, comprobando una evolución de especies a lo largo del tiempo, que había pasado inadvertida. Se han utilizado aislados obtenidos de plantas enfermas de pimiento en varios invernaderos y en distintas anualidades entre 1997 y 2006. Los estudios morfológicos, fisiológicos y de patogeneicidad han permitido poner de manifiesto que la especie predominante de Phytophthora en los invernaderos del Campo de Cartagena es P. parasitica, lo que contrasta con estudios precedentes en los que P. capsici era la especie mayoritariamente encontrada. Las variaciones observadas hacen plantearse preguntas sobre las causas que han originado o facilitado los cambios, que parecen consolidados. -En condiciones controladas y estudiando suelos de invernaderos con diferentes antecedentes de antigüedad del monocultivo y forma de desinfección, se ha caracterizado la fatiga del suelo, que provoca grandes pérdidas debido al monocultivo de la zona, utilizando como indicadores el pimiento, el apio y la lechuga. Se ha encontrando una importante especificidad para el pimiento debida a la componente microbiológica seleccionada a lo largo del ciclo de cultivo o de permanencia de las plantas en el invernadero. -Desde la prohibición del bromuro de metilo en 2005 se han venido evaluando distintas enmiendas para utilizar como biofumigantes intentando encontrar las más adecuadas para el control de patógenos, sin tener que alterar el ciclo habitual del cultivo de pimiento en las zonas del sur de Alicante y Campo de Cartagena, así como evaluar su eficacia desinfectante para el control de los dos principales patógenos en el tiempo. La biosolarización con estiércoles frescos iniciada en agosto proporciona resultados satisfactorios para el limitar la incidencia de la “tristeza del pimiento”, e inciertos para el control de Meloidogyne incognita. Algunas enmiendas mejoran los efectos de la biosolarización con estiércoles, cuando se inicia la desinfección en octubre coincidiendo con el final del ciclo habitual del cultivo, si bien los niveles de control de Phytophthora spp. y Meloidogyne incognita son insuficientes en algunos invernaderos y años. [ENG] Sweet pepper crops represent an important part of the agricultural economy of the province of Murcia. This is particularly true in the Campo de Cartagena region, where its cultivation occupies 2000 ha of greenhouses. However, the monoculture of sweet pepper has led to the presence of specific pathogens such as Phytophthora spp., the cause of an important disease and Meloidogyne incognita, which have become limiting factors for the crop and the cause of serious economic losses. The prohibition of methyl bromide because of its harmful effect on the environment following years of use to disinfect the soils in which pepper has been cultivated, has led to the search for alternatives that are both sustainable and lasting. For this reason it is so important to update our knowledge of the main pathogens involved and cultivation techniques used, particularly those causing plant death, the characteristics of soil fatigue and on the biosolarization (biofumigation plus solarization) as a methodology for disinfecting the soils. We characterized the pathogen causing pepper disease as a prior step to establishing non-chemical strategies for its control, observing in the process that there had been an evolution in the species involved that had passed unnoticed. Isolates obtained from diseased pepper plants from several greenhouses during the years 1997 to 2006 were used. Morphological, physiological and pathogenicity studies revealed the predominant species of Phytophthora in the greenhouses of Campo de Cartagena to be P. parasitica, which contrasts with previous studies in which P. capsici was seen to be the main species, a situation that had not been noticed until our study. The variations observed pose questions regarding the causes giving rise to or facilitating such changes which, moreover, seem to be permanent. In controlled conditions we studied the soils of greenhouses supporting a different number of years of monoculture and the form of disinfection used in order to characterize soil fatigue, the cause of large losses, using as indicators pepper, celery and lettuce. A high degree of specificity for pepper was found due to the microbiological component selected during the crop cycle or length of time the plants had been in the greenhouse. Since methyl bromide was banned in 2005, we have evaluated different amendments for use as biofumigation elements in order to control the pathogens while not affecting the normal crop cycle in the area south of Alicante and the Campo de Cartagena, evaluating their ability to control the two main pathogens at the same time. Biosolarization with fresh manure beginning in August provided satisfactory results as regards limiting the incidence of Phytophthora sp. wilt but not such good results for controlling Meloidogyne. Some amendments improved the effects of biosolarization with manure, when example beginning in October coinciding with the end of the normal crop cycle, although the level of control of Phytophthora spp. and Meloidogyne incognita remained insufficient in some greenhouses and in some years.[ENG] Sweet pepper crops represent an important part of the agricultural economy of the province of Murcia. This is particularly true in the Campo de Cartagena region, where its cultivation occupies 2000 ha of greenhouses. However, the monoculture of sweet pepper has led to the presence of specific pathogens such as Phytophthora spp., the cause of an important disease and Meloidogyne incognita, which have become limiting factors for the crop and the cause of serious economic losses. The prohibition of methyl bromide because of its harmful effect on the environment following years of use to disinfect the soils in which pepper has been cultivated, has led to the search for alternatives that are both sustainable and lasting. For this reason it is so important to update our knowledge of the main pathogens involved and cultivation techniques used, particularly those causing plant death, the characteristics of soil fatigue and on the biosolarization (biofumigation plus solarization) as a methodology for disinfecting the soils. We characterized the pathogen causing pepper disease as a prior step to establishing non-chemical strategies for its control, observing in the process that there had been an evolution in the species involved that had passed unnoticed. Isolates obtained from diseased pepper plants from several greenhouses during the years 1997 to 2006 were used. Morphological, physiological and pathogenicity studies revealed the predominant species of Phytophthora in the greenhouses of Campo de Cartagena to be P. parasitica, which contrasts with previous studies in which P. capsici was seen to be the main species, a situation that had not been noticed until our study. The variations observed pose questions regarding the causes giving rise to or facilitating such changes which, moreover, seem to be permanent. In controlled conditions we studied the soils of greenhouses supporting a different number of years of monoculture and the form of disinfection used in order to characterize soil fatigue, the cause of large losses, using as indicators pepper, celery and lettuce. A high degree of specificity for pepper was found due to the microbiological component selected during the crop cycle or length of time the plants had been in the greenhouse. Since methyl bromide was banned in 2005, we have evaluated different amendments for use as biofumigation elements in order to control the pathogens while not affecting the normal crop cycle in the area south of Alicante and the Campo de Cartagena, evaluating their ability to control the two main pathogens at the same time. Biosolarization with fresh manure beginning in August provided satisfactory results as regards limiting the incidence of Phytophthora sp. wilt but not such good results for controlling Meloidogyne. Some amendments improved the effects of biosolarization with manure, when example beginning in October coinciding with the end of the normal crop cycle, although the level of control of Phytophthora spp. and Meloidogyne incognita remained insufficient in some greenhouses and in some years.Universidad Politécnica de Cartagen