"I'm going to wade into this one. As a First Detector Specialist, I have been working with the A&M Plant Pathology Lab for three years now on Citrus Canker so I do have some information to share. The quarantine areas are set by the TDA through a court order. The Citrus Greening was set up per county lines. Citrus Greening is considered cautious but to date there have been NO in-ground trees testing positive for Greening. One can bring citrus into the three county quarantine if it is certified from a HLB-free facility. You are allowed to move citrus around inside the three counties. The Citrus Canker is very serious because it is Strain A, the most widespread and severe form of the disease. The strain in Rancho Viejo is a different and only attacks lemons and limes. The quarantine area for Citrus Canker is set up per square mile. The area has increased in size three times since July 28th and is set to be increased again in two weeks. The purpose of the quarantine is to eradicate the bacterium. TDA and USDA are canvassing the homeowners,testing trees and trying to remove them. This is a huge task since each tree is removed by persons completely suited, the trees are cut and bagged to be hauled off then the area is drenched. There are (to date) 645 positive trees just in Fort Bend. Harris has 33. Of the 645 trees, only 350 have been destroyed. Legally, they can only take positive testing trees but if a homeowner refuses destruction a court order is obtained to take it our. It is important that no citrus or citrus parts are moved into the area because of the possibility of re-infection. Also important no citrus or citrus parts leave the area since the bacterium can live on twigs, fruit, leaves...any part. As for preventative, A&M suggests owners use approved insecticides to minimize common insect damage since leafminer galleries are the most common avenue of infection. Preventive bactericides common for citrus are copper products. Look for neutralized copper sulfate or copper hydroxide products. Each must be labeled for citrus."