The Citrus Research and Development Foundation (CRDF) board of directors meeting in July focused largely on the use of oxytetracycline (OTC) as an HLB treatment in citrus. The board considered projects testing it in combination with other antimicrobial compounds or as a standalone treatment.
Trunk injection of OTC has given the Florida citrus industry hope that it might be a viable treatment and bridge to a longer-term solution to HLB.
“While there is literature to suggest that resistance to OTC by the HLB pathogen is likely much farther out than some think, we should have a backup antimicrobial ready in case resistance develops,” said CRDF chief operating officer Rick Dantzler. “There also might be ways to increase the potency of OTC or combine it with something else that might be effective against other diseases. The expense of applying OTC (via trunk injection) is significant, so we are looking for ways to give the tree other products it could use while this expense is being incurred.”
The CRDF board turned down two proposed projects and asked researchers on three other projects to come back with more information to support their proposals. All of these proposals had to do with maximizing the efficacy of OTC or developing substitute products.
The board also voted to repeat a plant growth regulator (PGR) trial to see if the results can be replicated. Benefits were noted in some treatments but not in others.
“With last year’s hurricanes, the results on the PRG trial could be skewed, so we need to do this again to make sure,” Dantzler said. “This is a therapy that has been shown to work as an HLB treatment, so we need to find out for sure.”