The chestnut gall wasp Dryocosmus kuriphilus is a major insect pest affecting chestnut trees worldwide. Medium and long-term control of this pest can be improved by using resistant or less susceptible cultivars and hybrid clones. In addition, little is known about the local patterns of dispersal of the pest. We obtained data from trees of 3 chestnut species and 27 hybrid clones in a field trial in NW Spain with the aim of evaluating the susceptibility of the material to the gall wasp and identifying possible drivers of local spatial dispersal. In the first 3 years of the invasion by D. kuriphilus, the number of trees attacked and the number of galls on each tree were spatially clustered. Tree height significantly predicted both variables, suggesting that gall wasps may use visual cues to locate suitable host trees, at least in the early stage of invasion. Assessment of the susceptibility of hybrid clones/pure species must take concurrent indicators of infestation levels into account. We suggest the use of indices involving galls on shoots because these enable good assessment of the damage to chestnut trees. The study findings add to existing knowledge on the susceptibility of hybrid chestnut clones. We report, for the first time, two hybrid clones resistant to the pest and one hybrid clone which exhibited consistently low values for all of the indicators of infestation level. The results have important implications regarding selection of plant material for use in afforestation in Spain, where the current high rate of chestnut planting is expected to continue.

Se presentan los trabajos que realiza el vivero de TRAGSA en el ámbito de la sanidad forestal, en cuanto al desarrollo de Materiales Forestales de Reproducción con tolerancia a enfermedades, en la producción de parasitoides para el control biológico de plagas forestales, y en el desarrollo de metodologías de teledetección para detección temprana, caracterización y seguimiento del estado fitosanitario de las masas forestales. Se describen los trabajos realizados y en curso al respecto de la obtención de MFR de castaño, de encina y alcornoque por tolerancia a Phytophthora cinnamomi, y de Alnus glutinosa por tolerancia a P. alni. Así mismo se presentan los trabajos de estudio de Torymus sinensis para la lucha biológica contra Dryocosmus kuriphilus, y de producción de Anaphes nitens para la lucha biológica contra Gonipterus platensis. Por último se comentan los trabajos realzados con RPAS para detección y seguimiento de Armillaria mellea en masa de Pinus pinaster.

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