In the absence of any phytosanitary controls the overall probability of entry of Phytophthora ramorum is considered to be high, mainly due to the wide host range and the ability of P. ramorum to persist in a variety of substrates (e.g. soil, growing media, bark, wood, foliage).

The probability of establishment in the PRA area is high. 

The potential economic impact for the nursery trade is high. Without controls the pathogen has the potential to spread further in the trade network and could potentially expand its host range, which is already very wide. For cultivated plants, damage is principally to the quality of hardy ornamental hosts. Loss of exports may increase if third countries maintain requirements for imports of ornamental plants from the EU.