Photo by Dave Hall
The most devasting disease to impact Florida citrus production is a threat to trees in the cold-hardy citrus region. Citrus greening disease has impacted Florida groves for more than 20 years and looms as a danger to trees in South Georgia, North Florida and South Alabama.
While the best management strategy is prompt removal of trees, a longer-term solution is still needed. That’s easier said than done, according to Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist.
“The symptoms of the disease don’t show up sometimes for several years after the plants get infected. But before symptoms show up, theoretically, the plant has the bacteria that causes the disease, and psyllids — the insect vector of the disease — can pick it up and move it around,” Oliver said. “It can spread in a wide area before you even realize you have a problem. It’s really hard to stay out in front of it. It’s almost impossible.
“Plus, the psyllids seem to reproduce very quickly and very well. We sometimes find the disease in areas without the psyllids. So, it seems like sometimes the psyllids can just pop in, be there, transmit the bacteria and then move out. Controlling it just at the psyllid level can be challenging as well.”
Psyllids also appear to not be fazed by the colder temperatures in the cold-hardy citrus region.
“We definitely have seen psyllid populations that are present one year and then overwinter until the next year. We see it in the same grove early in the season,” Oliver said. “We assume they stayed there over the winter. At least some individuals stayed there in order to reestablish the population the next year.”
Citrus greening has led to more than 90% decline in Florida production since the disease’s initial discovery in 2005.
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