“…and tanoaks (Notholithocarpus densiflorus) and shown to be the causal agent of the observed outbreaks. Discovery and research milestones of this decade included (i) the determination that P. ramorum was also the causal agent of a leaf and branch dieback of ornamental plants, later named ramorum blight, which affected rhododendrons and viburnums in German and Belgian commercial plant nurseries (123,124), (ii) the discovery that ramorum blight was also present in U.S. and European nurseries outside Belgium and Germany (29,37,114), (iii) the determination that P. ramorum was mostly an aerially dispersed oomycete (25,28,86) and in fact the first forest Phytophthora ever to have been described with such a transmission mode in the temperate zone (several others were to be discovered in the years to follow), (iv) the discovery that infectious airborne sporangia were not produced in significant numbers on the bole lesions responsible for oak and tanoak mortality but rather were extremely abundant on foliar lesions of a newly discovered host, California bay laurel (Umbellularia californica) (25,28), and on the leaves and twigs of tanoaks (26,27), (v) the progressive discovery that over 100 species could be infected by the pathogen, including both U.S. native and ornamental species (29,43,114), (vi) the determination that the source of the California infestation could be traced back to infected ornamental plants (22,81,101) and that the pathogen itself was comprised of four genetically distinct lineages, each with a fixed mating allele (52,66,67,117,125), (vii) evidence that the pathogen could be retrieved from soil and water in both forests (25,41) and nurseries (107), (viii) the understanding, based on the sequencing of the entire genome (115), that while sexual reproduction in P. ramorum currently appears to be absent and not fully functional (5,10,…”