El incremento en severidad de las epidemias de Verticilosis del olivo (VO) ha ocurrido de manera paralela a la implantación del riego en nuevas plantaciones y en plantaciones de olivar tradicional en Andalucía. El agua de riego puede influir sobre la VO por actuar como vehículo de dispersión de los propágulos de Verticillium dahliae. Por todo ello, los objetivos planteados en esta investigación han consistido en determinar y cuantificar la presencia de V. dahliae en el agua utilizada para el riego de olivares en Andalucía, y estudiar la evolución temporal de los niveles de dichos propágulos durante la temporada de riego. Se han prospectado un total de 33 campos de olivo afectados por la Verticilosis en las provincias de Jaén y Sevilla en los años 2004 (5 y 18, respectivamente) y 2005 (7 y 14, respectivamente), siendo 11 de los campos comunes en ambos años de muestreo. En cada campo, se analizaron 2-8 muestras de 0,5 L de agua de riego obtenidas desde marzo hasta julio del año 2004, y 3-4 muestras de 1000 L de agua recolectadas desde febrero hasta abril del año 2005. V. dahliae se aisló sólo de las muestras de agua analizadas en el año 2005. El patógeno se recuperó del agua de riego del 85,7% de los campos prospectados en cada provincia, que representaron el 87,5 y 80% del total de campos regados con agua de pozo y agua superficial embalsada de origen en el río Guadalquivir, respectivamente. Independientemente de su origen, el agua de riego de ambas provincias estuvo infestada por propágulos de V. dahliae que, según su tamaño, se diferenciaron en esclerocios (>/= 20 micro m) y micropropágulos (<20 y >/= 1,2 micro m). Los micropropágulos se recuperaron del agua de riego de un porcentaje mayor de campos que utilizaron agua infestada (78%) y en mayores cantidades promedio (3158,9 micropropágulos/1000 L) que los esclerocios (44% y 1,5 esclerocios/1000 L, respectivamente). Entre los campos que emplearon para regar agua infestada por V. dahliae, la incidencia de campos con agua contaminada por esclerocios varió de 0 a 33% durante la temporada de riego y no siguió un patrón temporal reconocible, mientras que el porcentaje de campos con agua infestada por micropropágulos alcanzó un máximo de 33% en Jaén y 75% en Sevilla en la segunda y primera quincena de Marzo, respectivamente, y disminuyó progresivamente durante los muestreos de primavera. | The increment in severity of Verticillium wilt epidemics of olive trees has been associated with the establishment of irrigation in new and traditional olive orchards in Andalucía. Irrigation water can influence Verticillium wilt of olive (VO) by means of the dispersal of propagules of Verticillium dahliae. Therefore, the objectives of this research work were to determine and quantify the presence of V. dahliae in the irrigation water used in olive orchards in Andalucía, and to study the variation in the level of the pathogen populations over time during the irrigation season. Disease surveys were carried out in 33 olive orchards affected by Verticillium wilt at the Jaén and Sevilla provinces in 2004 (5 and 18 fields, respectively) and 2005 (7 and 14 fields, respectively), with 11 of the fields being prospected in both years. In each field, 2-8 irrigation water samples of 0.5 L obtained from March to July in 2004 and 3-4 samples of 1000 L of water collected from February to April in 2005 were analysed. V. dahliae was isolated only of the water samples analysed in 2005. The pathogen was recovered of irrigation water in 85.7% of the olive orchards surveyed in each province, representing 87.5 and 80% of total of fields irrigated with subterranean water from wells and dammed up superficial water from the Guadalquivir river, respectively. Subterranean and superficial irrigation water in both provinces were infested by propagules of V. dahliae, which were differentiated because of their size in sclerotia (>/= 20 micro m) and micropropagules (<20 y >/= 1.2 micro m). The micropropagules were recovered from irrigation water in a higher percentage of fields that used infested water (78%) and in higher average levels (3158,9 micropropagules/1000 L) than sclerotia were (44% y 1,5 sclerotia/1000 L, respectively). Within the olive orchards irrigated with water infested by V. dahliae, the incidence of fields with water contaminated by sclerotia varied from 0 to 33% through the irrigation season and did not show any recognizable pattern over time, while the percentage of fields with water infested by micropropagules reached a maximum of 33% in Jaén and of 75% in Sevilla in the second and first fortnight of March, respectively, and decreased progressively through the spring samplings.

During a general malacological survey for freshwater gastropods in northern Patagonia, a population of Biomphalaria was encountered at Agua Escondida. Biomphalaria spp. are freshwater pulmonates of biomedical importance, uncommon in Mendoza Province, and often act as intermediate hosts for Schistosoma mansoni. By looking at both morphological and molecular characters, we describe a detailed process of identification and characterization of Biomphalaria peregrina from a location towards the extremity of its species range. A reference DNA ‘barcode’ is presented. As B. peregrina has been shown to be a permissive experimental host of S. mansoni, snails were also screened in the field for schistosomiasis and later in the laboratory using a novel polymerase chain reaction-based assay but no infections were found. Considering the transmission potential of this species, increased vigilance for intestinal schistosomiasis is recommended, especially if local environmental conditions become favourable for disease transmission, for example, through future climate change and intensification of irrigation.