<i>Phytophthora chrysanthemi</i> (Naher, Hi. Watan., Chikuo & Kageyama)
In 1998 a root rot on Chrysanthemum caused by an unknown Phytophthora species was observed in Japan. In 2003 the pathogen was detected again in Japan, in hydroponically grown potted chrysanthemum (Watanabe et al. 2007). This unknown Phytophthora species was identified as Phytophthora chrysanthemi sp. nov. (Naher et al. 2011).
In Europe P. chrysanthemi was first detected in Croatia in 2008 and 2009 (Tomić and Ivić 2015) on Chrysanthemum cultivated in a nursery. In 2015 P. chrysanthemi was detected in a German ornamental nursery on Chrysanthemum indicum (Götz et al. 2017). A further Phytophthora isolate detected in a German ornamental nursery in 2016 was also identified as P. chrysanthemi (Götz, Ulrich, Werres, unpublished data).
Recently P. chrysanthemi was detected in the United States on Chrysanthemum x morifolium ‘Aubrey Orange’ and ’Fancy Ursula Orange’ (Lin et al. 2017).