2. Oleander shrubs, Nerium oleander, have been dying at a rapid rate all over Orange County due to a recently identified plant disease in Southern California. The disease, caused by the bacterium Xylella fastidiosa, has caused widespread destruction of Oleander. Symptoms appear initially as leaf tip dieback that become progressively worse through the summer, eventually infesting entire branches. As the disease spreads, more of the plant dies. The entire plant will die within about one year of initial infection. At present there are no effective controls, but one means of limiting the spread is to disinfect pruning tools before use on healthy plants. Research shows that plants most susceptible to the disease are those under heat or water stress.