The treatment for English ivy diseases depends on the specific disease and its severity. For bacterial or fungal infections, removing and destroying infected leaves or stems can help slow the spread of the disease. For insect infestations, use insecticidal soap or neem oil to control the pests. Finally, ensure that the ivy is getting adequate light, water, and nutrients to prevent environmental stress. If the disease is severe, consult a professional gardener or horticulturist for advice on treatment options.