Citrus exocortis is a disease of citrus plants, caused by the Citrus exocortis viroid (CEVd). It can causes stunted growth and reduced yields in affected plants. The disease is also sometimes called "scalybutt".
CEVd can also infect tomato plants. The resulting disease is sometimes called "tomato bunchy top disease."
References
Citrus exocortis Wikipedia(Text) CC BY-SA