NATIVE RANGE: North America and Japan

FIRST FINDING IN SLOVENIA: not yet found in Slovenia

PATHWAYS: transport with infected saplings

POSSIBLE TO FIND: yearround

DESCRIPTION: The first symptom is the appearance of yellow spots on the upper sides of the leaves, which later progress to necrotic brown spots. These coalesce and eventually cover large parts of the leaf. Yellow-orange fruiting bodies develop on the undersides of leaves, and sometimes later also on fruits.

HOST PLANTS: The most commonly affected species are American blueberries (Vaccinium corymbosa) and other species from the heather family (Ericaceae). Native European blueberries (V. myrtillus) are not known to be affected. Hemlocks (Tsuga spp.) act as intermediate hosts.

STATUS: In Europe so far found in Germany, Belgium, the Netherlands and Portugal. Likely to spread with the trade in American blueberry saplings.

SIMILAR SPECIES: All other rusts on American blueberries, for example Pucciniastrum vaccinii are similar and microbiological analysis is needed to confirm identification.

SOURCE: Field Guide to Invasive Alien Species in European Forests