Ornamental and native foliage can fall victim to disease and insects. The increase of these infected plants adds to the overall fire danger risk in Orange County, CA. These infected plants should be removed after they have died.
1. Eucalyptus Trees. Remove all fallen leaves, limbs, litter, debris and loose bark from the ground. Dead trees should be removed, depending upon location. Note: the Eucalyptus longhorn borer, Phoracantha semi-punctata, has been infesting eucalyptus trees in this area. Many of these trees are dead or dying.
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 becomes progressively worse throughout 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 the initial infection. Presently, 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.
3. The redgum lerp psyllid was found in redgum eucalyptus trees in Los Angeles in 1998 and has spread throughout much of California. Psyllids are plant-juice sucking insects that form a cover called a "lerp" which is a small white, hemispherical cap. The psyllid tends to attack trees already under stress due to draught. While the lerp psyllid is not lethal to the tree, its presence can contribute to the tree's death.