Occurrence of Phytophthora Root and collar rot disease of Chamaecyparis and Thuja in Tonekbon area in the west part of Mazandran,North of Iran
High rot of the root and crown of the Chamaecyparis and Thuja due to Phytophthora fungus occurred in Tonekabon area from north of Iran in winter of 2014 and in spring of 2015. The symptoms like yellow,wilting and fall of the needles, root and crown rot and dry shrubs were observed in infected conifers shrubs. The disease is poorly drained soil in gardens, ornamental cedars production was observed in 20 of 30 nurseries. The appearance of Camaesyparis and Thuja infected in the lands with heavy soils more than 60 and in some of production nurseries reached to 100 percent. The element of the disease and pathogen was characterized based on mycology properties, Phytophthora sp, where the symptoms and the element of this disease completely conform to internal and external sources.