DISCUSSION
This is the first report of bacterial brown
leaf spot (BBLS) of citrus, a new and apparently
opportunistic bacterial disease of
citrus. Typical symptoms of the disease are
flat, circular, brownish lesions with
slightly raised and water-soaked margins
surrounded by a chlorotic halo. The occurrence
of the disease in the field was consistently
associated with storms that caused
damage to citrus, indicating the bacteria
infected citrus plants via wounds. By fulfilling
Koch’s postulates and discerning
that the causal agent was indeed a bacterium,
we eliminated other diseases of citrus which display similar phenotypes.
These included the fungal diseases: greasy
spot (Mycosphaerella citri) (31), Phaeoramularia
fruit and leaf spot (Pseudocercospora
angolensis), and Alternaria brown
spot (Alternaria citri) (7,25).