One or two ivy leaves gone could be a simple gust of wind, but mass leaf loss means trouble. Ivy plants grown indoors or outdoors develop a number of diseases and pest problems with leaf drop or leaf loss as a prime symptoms. Each problem leaves clues helping identify it and apply the right treatment.
If your indoor ivy plant is losing leaves, especially over the winter months, an environmental imbalance may be responsible. Ivy plants placed too close to drafty doors or window lose leaves. Dry, winter air from using heat in can also makes the plant lose leaves. If your plant leaves wither, turn black and then fall off, consider changing something in the environment. Move your plant to a less drafty spot or increase the humidity with a humidifier.
Insect pests damage ivy plants, causing leaf loss. If your ivy leaves feel sticky, turn yellow and fall off, insects are the likely cause. Scale, aphids and mealy bugs may be infesting the plant. Insecticidal soap applications treat the infestations.
Plants afflicted with anthracnose or bacterial leaf spot experience leaf dieback and leaf drop. Ivy plants developing black spots on the leaves probably have one of these diseases. Treat the ivy with fungicide and remove all discolored shoots.
Rhizoctonia Root Rot and Aerial Blight
Rhizoctonia root rot and aerial blight are two plant diseases occurring in tandem that are destructive to ivy plants. If ivy plants develop this type of root rot, wilting and dropping leaves occur. Additional symptoms include brown lesions on the leaves and reddish blotches on the foliage. Once your plant's roots begin rotting, there is nothing you can do. The ivy plant dies.