First notice of phytophthora crown and root rot of Euphorbia pulcherrima in Polish greenhouses.
The plant pathogen, Phytophthora cryptogea, was recovered from 4/5 of the 75 poinsettias collected from two greenhouse farms. The poinsettias showed stunting and wilting as well as stem base and root rot symptoms. Representative isolates of the species from two poinsettia cultivars, colonized stem parts, leaf petioles, leaf blades and root parts. Stem parts of 6 cultivars were colonized at a slower rate than other poinsettia organs. Isolate from Euphorbia pulcherrima also colonized stem parts and leaf blades of E. amygdaloides, E. cyparissias, and E. polychroma. Isolates of P. cryptogea from the other 6 plant hosts, colonized the overground parts of poinsettia cv. Allegro. This is the first report describing symptoms and colonization of poinsettia cultivars by P. cryptogea in Poland.