For early information regarding Citrus Canker please check out The Historical Museum of Southern Florida
Citrus canker, a bacterial disease, was found in 13 locations of 4 Florida counties between 1986 and 1992. Bacterial citrus canker had been declared erradicated from Florida in 1933 after more than 258,000 grove trees and 3 million nursery trees were detroyed (more than $6 million was spent for this erradication effort). By 1934 more than 20 million (cost exceeding $25 million) trees had been destroyed along the Gulf Coast (Florida to Texas). To maintain an citrus canker free area for such a long time was done by using stringent border inspections of fruit and plants. Also quarantine restrictions required that infected trees and all plant material within 125 ft must be burned. Citrus workers wore clothing that was easy to remove at the fields and machinery was thoroughly cleaned after work in a grove. Shipments of citrus was only to non-citrus growing states. The 2000 season is already starting to feel the effects of citrus canker as 4 counties in Florida were declared as agricultural disastor areas.
So
what does citrus canker do to the citrus plants and what causes it?
Xanthomonas citri, a bacterium, overwinters in leaf, twig, and fruit canker lesions. An ooze comes out of the lesions during warm, rainy weather and the bacteria is splashed onto tissue. It enters through stomata or wounds. Lesions appear on tissues and fruit as slightly raised, round, light green spots. Eventually they turn grayish and rupture, to appear corky with brown sunken centers. Severely infected fruit appear scabbed and deformed.
Control of this pathogen once it is in an area is dependent upon erradicating the pathogen. This is done by burning and detroying infected trees.
