Huanglongbing (HLB), Citrus Canker, and Citrus Black Spot were all at one time considered exotic citrus diseases. These diseases, especially HLB and Canker, have profoundly changed the way we grow citrus in Florida and have been economically devastating to our industry. Any exotic disease, if introduced, may further increase production costs and decrease profitability for Florida growers. Exotic diseases will affect the viability of the industry and the varieties that could be profitably grown. Not only is the environment here in Florida favorable to these exotic diseases, but also there are established populations of the insect vectors already in the state for three of the diseases. The disease triangle below shows the three elements needed for disease infection. A fourth element, the vector, is needed for diseases spread by insects. All three or four elements must be present for a disease to occur and spread. In Florida, we have the susceptible host, citrus, and we have the favorable environment. If the pathogens of these exotic diseases enter Florida, the potential for a disease outbreak is imminent.