Abstract

Horse chestnut (Aesculus hippocastanum) is mainly grown in gardens, public parks and alleys in Norway. It has been known as a tree with no disease problems, but since 2006, a number of new diseases have been detected (leaf blotch, powdery mildew, anthracnose, and bleeding canker). These new diseases have most likely entered the country by imported horse chestnut transplants. The diseases mentioned here may reduce the aesthetical value of horse chestnut to such an extent that we no longer recommend it for planting in Norway. Fortunately, the insect horse chestnut leaf miner (Cameraria ohridella) has not yet been found in Norway.

Key words: Aesculus hippocastanum, Guignardia aesculi, Erysiphe flexuosa, Colletotrichumspp., Pseudomonas syringae pv. Aesculi.