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Keeping Young Trees Free of HLB

Ernie NeffHLB Management, Thermotherapy


megan dewdney

Plant pathologist Megan Dewdney was one of the University of Florida Institute of Food and Agricultural Sciences researchers who summarized scientific presentations made at the 2017 International Research Conference on HLB. She and others spoke at an HLB Grower Day in Lake Alfred, putting the complex presentations into terms more understandable to those who aren’t scientists. Dewdney discussed young tree care, HLB detection and thermotherapy timing.

Dewdney emphasized the importance of keeping young trees free of HLB for their first three years by keeping them free of Asian citrus psyllids. “Probably the most important thing about taking care of young trees … is really looking at your psyllid control,” she said. “Is it adequate to try and keep those trees protected for at least those first three years? … Do you have neighbors that have abandoned groves or semi-managed groves?” In semi-managed groves, growers may be fertilizing “but they aren’t doing much in terms of psyllid control,” Dewdney said. “These are probably the ones, the semi-abandoned ones, that are probably the most productive in terms of psyllids. And if you have a large number of psyllids coming in, it’s very, very difficult to protect the trees by any means to keep them viable.”

Dewdney summarized research from Texas indicating that HLB is more easily detected in tree roots than in the canopy. “It is very difficult to pick the right leaves that might have the bacteria in them,” she said. She added that bacteria seems to be more evenly distributed in roots. “So, if you have suspicions that you’re not getting any positive results from leaf analysis … Texas is recommending … looking at testing the roots to see which ones are truly symptomatic.”

Regarding timing of thermotherapy to reduce HLB bacterial levels, Dewdney said, “It looks like the winter seems to have the greatest total reduction in bacteria.”

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About the Author

Tacy Callies

Editor of Citrus Industry magazine