NATIVE RANGE: unknown

FIRST FINDING IN SLOVENIA: 2003

PATHWAYS: transported with infected soil (including soil fragments on boots and vehicles), saplings and on clothes. 

POSSIBLE TO FIND: year-round

DESCRIPTION: The genus Phytophthora has over 140 species. The most common native species are P. citricola and P. cambivora. P. ramorum which causes leaf blight and dieback, was first found in Europe in 1997 and is listed as a quarantine pest. Symptoms include the dieback of shoots and twigs, necrotic lesions on leaves and lesions on the bark, which exude a dark fluid. Infections cause dieback of various woody plants.

HOST PLANTS: Host species in forests include oaks (Quercus spp), beech (Fagus sylvatica), sweet chestnut (Castanea sativa), sycamore (Acer pseudoplatanus), common ash (Fraxinus excelsior), guelder rose (Viburnum opulus), blueberry (Vaccinium myrtillus) and European larch (Larix decidua).

STATUS: Widespread throughout Europe. In Slovenia, Phytophora is regularly found at border controls of imported ornamental bushes and trees. It has also been found in parks, however, it was eradicated in all known cases.

SIMILAR SPECIES: All Phytophthora spp. cause similar symptoms on deciduous and coniferous trees. Identi-fication is only possible in the laboratory. Exudates can also be caused by insects including wood-boring beetles. In this case, there are visible holes in the trees, galleries, bore-dust, sawdust, larvae or adult insects.

SOURCE: Field Guide to Invasive Alien Species in European Forests