Moving citrus trees from a quarantine zone into an area not under quarantine is the fastest way that citrus diseases are spread. There are four serious citrus diseases found in the United States include Huanglongbing (also known as citrus greening or HLB for short), citrus canker, citrus black spot, and sweet orange scab.  Our Gulf coast counties are quarantined for three out of the four. Learn more about each disease by visiting the Citrus Survey Program page on the Alabama Department of Agriculture website.  Without proper biosecurity practices in place, when infected trees, fruit, clippings, equipment or even workers are moved to a new area, the disease comes with them. It is not just commercial citrus that is susceptible to these diseases. Homegrown citrus trees can easily become infected and spread disease.