Citrus Diseases Exotic to Florida: Black Spot1

Citrus is susceptible to a large number of diseases caused by plant pathogens. Economic losses due to plant diseases can be severe, but fortunately, not all pathogens attacking citrus are present in Florida. Major citrus diseases currently present in Florida include tristeza, blight, greasy spot, Alternaria brown spot, Phytophthora-induced diseases, melanose, scab, postbloom fruit drop (PFD), and citrus canker. An exotic, destructive disease called citrus greening (Huanglongbing) has recently been found in Florida. There are several serious pathogens that have not been introduced into Florida. Any exotic pathogen, if introduced, has the potential to significantly increase production costs and decrease profitability for Florida growers. The background information for each exotic citrus disease will be presented in a series of fact sheets. Our intent is to: 1) provide a basis for evaluating exotic pathogens that may pose potential risks to Florida citrus; and 2) to create a decision-making framework to prevent their introduction and spread. This paper will discuss citrus black spot.