Deformed Flowers on Black Eyed Susan

This past year one of my black-eyed Susans formed a strange shape, almost like a set of lips with a yellow beard and a spiky hairdo. What caused this?

Aster yellows can cause distorted and green flowers on otherwise healthy looking plants. Black-eyed Susans, other members of the aster (daisy) family, and a variety of flowers and vegetables are also susceptible to this disease. Remove infected plants as soon as the symptoms appear. This eliminates the source of disease that can be transmitted by leafhoppers to healthy plants. Fortunately Black-eyed Susans reseed readily and there should be plenty of healthy offspring to take the place of infested plants. Control leafhoppers with insecticidal soap, Neem or another eco-friendly insecticide labeled for control of aphids on flowers. Controlling the aphids will reduce the spread of this disease.