Xylella fastidiosa is a gram-negative, aerobic bacterium, found in the xylem. It multiplies inside the vessels reaching to plug them and obstruct the flow of raw sap, which causes symptoms that correspond to lack of water or lack of nutrients in the plant or tree.
There are 3 main subspecies of the bacteria X. fastidiosa:
- Subsp. annoying
- Subsp. pauca
- Subsp. multiplex
In Europe, recombinants of these subspecies have appeared, as in the case of Italy that a recombinant of the Pauca subspecies called CoDiRO is present and in Corsica (France) that recombination between the multiplex-sandyi subspecies is present.
*Source picture Philaneus spumarius (Aphrophoridade): Russell F. Mizell, Peter C. Andersen, Christopher Tipping, Brent Brodbeck (University of Florida).