If you can’t see the symptoms, for a variety of reasons, it’s very hard to run a PCR test and get a positive test on a tree. That might be because the disease is unevenly distributed in the tree, and if you sample in the wrong spot it won’t show a positive result.  

“Regardless, the latency makes the disease hard to deal with.

“One of the things folks in Florida and California have advocated is actually testing the Asian citrus psyllids, the vector for the disease. For months we’ve followed their example and have been sampling tons of psyllids and had some positive hits.

“Based on the best estimates we have, there have been seven positive psyllids. Three of them were found within the five-mile quarantine and four were outside it. As we speak, we’re trying to figure out our next steps.”

The possibility of new quarantines/regulations…

“From a regulatory standpoint, the USDA, APHIS and the Texas Department of Agriculture don’t establish a new quarantine or take action based on positive psyllids. We must find the disease in tree tissue before regulatory action is taken.

“We’ve been speaking with scientists for whom we have high respect. I was speaking to one earlier today and it appears if you have a positive PCR sample from a psyllid, then that means you also have greening in plant tissue someplace. However, because of the latency issue and because it’s like finding a needle in a haystack, it’s hard to locate.

“So, the disease may have spread a bit in Texas. Even if that pans out, though, we’re optimistic that it hasn’t spread too far.

“For a variety of reasons — the positive psyllid finds and other things — the citrus industry has come together to say, ‘We need to ramp up all our efforts for psyllid control and everything related in dealing with this.’