The recent find of an infected adult Asian citrus psyllid in Santa Paula prompted the search for the potentially infected tree by CA Department of Food and Agriculture personnel to spread out to look and test.  Two trees were found and presumably they will be destroyed.  This now prompts a much more intense survey of the surrounding 2/10ths of a mile of those trees.  It also places a quarantine on the movement of fruit out of that area, extending out 5 miles.  That means no fruit or plant parts should be taken out of the area, potentially spreading the insects and disease to other areas, unless those plant parts have been properly treated. You can read more about the actions taken in a quarantine when infected insects or plants are found HERE .    And in this document you can read about the details in and around a quarantined area  and how the fruit and plants should be treated HERE.

As is the case in the spread of many invasive pests, it is humans that can be the main mode of movement of the pest and disease.