Citrus Greening disease (HLB) is the most devastating citrus disease in the world ravaging citrus growing areas everywhere. It is spread by the saliva of the Asian Citrus Psyllid which feeds on the leaves of citrus. The root systems of infected trees are poorly developed and new root growth may be suppressed. The disease spreads throughout the tree compromising nutrients from reaching the foliage and fruit, ultimately causing the decline and death of the tree.
The early symptoms of HLB on leaves are vein yellowing and an asymmetrical discoloration of leaves called blotchy mottle. It can take up to a year for the symptoms to appear after being infected. Much rood damage occurs before symptoms present. Other symptoms can include a notch in the leaves, irregular, discolored and bitter fruit; fruit drop; branch die-back; and ultimately, the death of the tree. All citrus varieties are affected by greening.
Greening was first discovered in south Florida in 2005 and has reduced citrus production significantly. All citrus-growing areas in Florida have been affected and the reduction in citrus production has significantly increased the price of citrus and juice in recent years. The citrus industry in Florida employs 75,000 and is a $9 billion industry.
There is no cure for greening but growers, scientists at the University of Florida, and the citrus growing industry have spent hundreds of millions of dollars to develop ways to combat the effects of greening. Fruit production yields by growers using specific maintenance practices have generally risen to their pre-greening levels.
Their research has resulted in new practices essential for growers and homeowners to keep their trees producing:
*Controlling the Asian Psyllid by using a systemic root drench containing Imidacloprid every two-months. Imidacloprid is the active ingredient used by many manufacturers of flea colors for pets. If used properly, imidacloprid is not absorbed into the fruit and flowers of the treated plants and any insects sucking juices from the leaves will die. We recommend and stock Dominion Tree and Shrub.
*Continual application of a superior control-release granular fertilizer made for our SW Florida climate on top and around the root system of all citrus trees. This will allow nutrition through the root-mass and carried through the Xylem into the foliage and fruit. We recommend using Nurseryman's Sure-gro All Purpose or their 8-2-12 palm fertilizer every three months.
*Spraying a liquid fertilizer created for citrus-greening onto the tree canopy on a regular basis throughout the year. This will provide essential nutrients directly to the plant's foliage. We recommend and stock KeyPlex Citrus HG.
*Minimizing stress to these trees by giving them regular watering throughout the year; avoiding the use of mulch; planting correctly and in sunny, well-drained soil; and keeping the area around the tree free of weeds and turf.