The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) hosted a statewide citrus grower workshop in mid-January at the Southwest Florida Research and Education Center in Immokalee.
The event offered a full day of education covering a wide range of topics, including management of pests, diseases, weeds and nutrients. Ute Albrecht, UF/IFAS associate professor of plant physiology, provided an update on her research on the use of oxytetracycline (OTC) as an HLB therapy.
She also addressed the use of ascorbic acid (vitamin C) as a potential way to give the OTC formulation more longevity. The idea was discovered by growers last year and taken to her for more formal research.
Her research showed that it takes a lot of ascorbic acid to get the OTC solution at the desired level. A field trial demonstrated that ascorbic acid didn’t improve the performance of OTC compared to currently labeled recommendations, and in some cases, might even reduce OTC performance.
“OTC works perfectly fine, so just focus on doing it right by following the label instructions,” Albrecht said. “If you want to do it better, consider making injections on both sides of the tree to better distribute the OTC.”
For growers who want to experiment with different additions to the mix, she advised to try it on a small number of trees first, because some additives might do more harm than good.
To reinforce the message, Albrecht shared data on her OTC trials, which have consistently shown improvements in yields. One trial was a commercial 20-year-old Hamlin grove, which has received an annual application for the past three seasons. Depending on the rate of OTC, the yields were double and triple (highest label rate) over the control where OTC was not applied.
Between seminars, hands-on demonstrations were set up at the workshop so growers could interact with scientists to learn more about specific research.
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