English ivy (Hedera helix) is an evergreen vine that is used as a ground cover in shady areas. It can be trained to grow on a trellis, as well as a rock, brick or other rough-textured wall or surface.
Conditions for Diseases
English ivy is more prone to leaf diseases during the wet season or when the foliage remains constantly wet from overhead irrigation. Leaf diseases can be particularly destructive and even fatal.
Fungal Leaf Spots
Fungal diseases cause reddish-brown to brown spots on the leaves of infected ivy plants. Phyllosticta concentrica causes the leaves to drop off and blights the twigs. Colletotrichum trichellum also infects the stems, causing them to collapse and die. Scabby raised brown spots are caused by Sphaceloma hederae.
Bacterial Leaf Spot
Pale green water-soaked spots are caused by the bacterium Xanthomonas hederae. The leaf petioles turn black and die too. The disease may spread into older wood and form cankers.
Other Leaf Diseases
Powdery mildew resembles patches of white dust on the leaves of affected plants. The patches can spread to cover the entire leaf. Gray mold is a fuzzy gray coating on affected leaves that also can cover the entire leaf.
Prevention and Treatment
Water English ivy early in the morning so the foliage can dry during the day. Remove and destroy any infected leaves or stems. Clean dead leaves and other debris from around plants. If fungal leaf spots have been a problem in past seasons, apply a fungicidal spray in spring and summer during active growth. Use a fungicide approved for English ivy and follow the manufacturer’s directions.