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Title:   Author  item
                                            Weiland, Gerald

                                                         - *Jerry*item
                                            GARRIDO, PATRICIA - Oklahoma State Universityitem
                                            Grunwald, Niklaus

                                                         - *Nik*item
                                            GARZON, CARLA - Oklahoma State University
  Submitted to: Phytopathology
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 3/28/2013
                                    Publication  Date: 11/1/2013
                                    Citation: Weiland, G.E., Garrido, P., Grunwald, N.J., Garzon, C. 2013. Exploring the characteristics of Pythium communities: Can knowledge about pathogen communities improve disease control?. In: Phytopathology. Annual Meeting of the American Phytopathological Society, August 10-14, 2013, Austin, Texas.Interpretive Summary:
                                Technical Abstract: Pythium species are an important component of the soilborne pathogen complex, causing damping-off of tree seedlings in forest nurseries. However, little is known about the phenotypic or genotypic diversity of forest nursery Pythium communities because disease control relies almost exclusively on chemical fumigants with broad spectrum efficacy. As fumigant use declines worldwide, knowledge about these communities will be necessary to develop new and more selective disease control measures. To this end, we are characterizing Pythium communities at three forest nurseries. To date, 19 Pythium species have been identified and population analyses indicate different degrees of genetic diversity for three commonly isolated species, P. irregulare, P. sylvaticum, and P. ultimum. In greenhouse trials with inoculated Douglas-fir seedlings, eight species each were categorized as either highly virulent or weakly virulent. In paired-culture assays, variation was observed among Pythium species and isolates in suppression by Streptomyces lydicus, a biocontrol agent. The variability found within these Pythium communities exemplifies the difficulty encountered in trying to find a single disease control measure to replace fumigation. An integrated pest management approach involving coordinated measures, each of which target a different component of a given pathogen complex, may be necessary to manage diseases caused by multiple pathogen species.


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