The common symptoms of an Azalea’s dieback are progressive death of twigs and branches. However, dieback is usually the result of insects or diseases.
The diseases that cause dieback in azaleas are two types of fungal diseases: botryosphaeria and phytophthora. Phytophthora is generally fatal, and the symptoms include leaves that go from pale green to yellow to brown, prematurely falling leaves and dieback. Botryosphaeria is a common azalea fungus, causing the branches to die, and leaves on the affected branches turn dark and roll up but do not fall off.
The insects that can cause dieback are the rhododendron borer and the rhododendron stem borer, two boring pests. Both pests prefer rhododendrons but are known to infest azaleas.
