Main research line: Diseases of Mediterranean Forests Ecosystems
Root rot caused by Phytophthora cinnamomi and Pythium spiculum
The root rot caused by the oomycetes P. cinnamomi and Py. spiculum, is the main problem affecting oak forests ecosystems in the Mediterranean climate regions. I have contributed on different projects with main goals center on epidemiological and aetiological aspect of both pathogens, as well as the integrated control strategies applicable to rangelands and woodlands ecosystems. The different actions against P. cinnamomi in which I have participated are:
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Cultural control focused on reducing the viable inoculum density by soil application of calcium amendments;
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Cultural control based on the abolition of the cultivation of susceptible species to the pathogen which favour its multiplication;
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Search for tree genitors resistant or tolerant to P. cinnamomi infection among natural morphotypes of Mediterranean Quercus especies
Currently, our most recent research lines about root rot control are focused on the development of biological control methods based on the circular economy of agrifood by-products as phytochemical compounds with anti-oomycetes action (thanks to an Emergia Project of Junta de Andalucía and a Project of Spanish Goverment).
Additionally, we are developed another new research line focused on Quercus ilex breeding against Phytophthora cinnamomi (thanks to a Spanish Goverment Project).
A research project in which I participate in collaboration with the National Institute for Agronomic Research (INIA) is developing an effective application of biofumigation with Brassica spp. to control the root diseases at dehesas. In the same way, I am part of a research group integrated by scientists of the Spanish Research Council (CSIC) and the University of Córdoba, which is looking for resistance against P. cinnamomi induced by the application of systemic phosphonate fungicides using trunk injection to control the root disease which is affecting the centenary cork oaks of Doñana Biological Reserve. Currently, I also start a study about the effects of the Climate Change, precipitations and warming, on P. cinnamomi epidemiology in Mediterranean forests.
Phytophthora cinnamomi is also a worldwide distributed pathogen which is causing severe mortalities of native flora in California. New introductions and outbreaks of the pathogen have been associated with the movement of plants and infested soil throughout and between continents. In this way, a microsatellite analysis of worldwide populations of P. cinnamomi was done to identifies global pathways of movement and the emergence of novel strains in California, during my postdoc stay at the University of California, Berkeley (USA). Additionally, the differential response of California native plants against worldwide P. cinnamomi genotypes was determine to assess the risk for flora survival derived of new pathogen introductions.
Canker caused by Botryosphaeria spp. on Quercus suber
Canker caused by Botryosphaeria spp. on Quercus suber: Trunk and branch canker caused by Botryosphaeraceae fungi is the most injurious disease for cork oak production. Until 2003, the standard commercial product Benomyl was effectiveness used to control the disease, however the exclusion of this product from the EU Pesticide Database requires the search for new choices to prevent cork oak cankering. During my research career, I have deal with canker control measures. The preventive application of different systemic or protective fungicides just after cork peeling shown an effective reduction of the length and number of cankers.
A highly significant contribution of this study was that the Spanish Government approved the temporally used of Thiophanate-methyl, one of the effective products, basing on the results obtained in this study.
The good results of this study have been published in a top-ranked journal (Forestry 88: 500-507) and honored with the Research Award ‘Abbás Ibn Firnás’ (2017).
Sudden Oak Death caused in California
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Sudden Oak Death (SOD) is caused by Phytophthora ramorum with severe mortality of the native flora in California, being especially susceptible endemic oaks and tanoaks. The pathogen biology is deeply affected by ecological conditions such as weather patterns and substrates, no study has yet comprehensively addressed the issue of pathogen population size, its genotypic diversity, and pathogen viability in different substrates in US nurseries and natural forests. During my research career, I have contributed on different projects with main goals focus on epidemiological aspect of P. ramorum, which are:
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The analysis of P. ramorum survival and spreading after a period with extreme drought conditions in natural infected forests.
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A comprehensive study of the population dynamics of P. ramorum in plants, soil and water during a year at a nursery research facility to establish the spreading and adaptive ability to different substrates under controlled-conditions.
The information generated is crucial to control the introduction pathways of the pathogen from nurseries into natural ecosystems. This last research project was made thank to the collaboration between the UC, Berkeley and the Dominican University of California (USA).
Wild olive diseases
Wild-olive ecosystems have a high ecological value in southern Spain. However, a severe decline leading to mortality has been observed affecting a wild-olive woodland in a protective area closed to Doñana National Park. Two Phytophthora spp., P. cryptogea and P. megasperma, as well as Pythium spiculum has been reported as the causal agents of this decline. Aetiology and pathogenicity aspects of these three oomycetes were established, such as temperature growth requirements, pathogenicity tests and biological consequences of these pathogens for the ecosystems conservation. The results obtained should be regarded in olive breeding programmes where wild-olive is used as a source of resistance to verticillium wilt.