It is a big problem and one that is growing larger all the time. Took a county extension course recently that devoted I would say a hour to hour and and half on citrus greening alone.
If I can find the materials I will post on here for reference for those interested in knowing how to id vs other symptoms such as the tree being deficient of one or more elements.
10% of your customers are 90% of the problem.
You may think the grass is GREENER on the other side, but if you take the time to water your own grass would be just as GREEN[/COLOR].