Citrus Greening Control and Increased Citrus Production on the Horizon

Aug 26, 2023

Florida citrus growers may have a new tool in the fight against greening.

Using a proprietary trunk injection system called "FlexInject," growers are able to directly apply a bactericide, oxytetracycline hydrochloride (OTC) ReMedium TI, which has shown promise in suppressing Candidatus Liberibacter asiaticus (CLas), the bacterium that causes the Huanglongbing disease (HLB) in citrus trees.

The FlexInject and ReMedium TI formulations were both developed by TJ BioTech. Currently, TJ BioTech and AgroSource, Inc. are the only two companies manufacturing this treatment. However, at least one more company is actively developing their own tree injection systems.

Although spray bactericides have had some benefit, the application is imprecise. More product is used to cover the full area, which can also impact other non-infected plants. Using the directed injection allows growers to focus their treatments on trees that are infected, using less product and minimizing the impact to the surrounding environment. As for application time, a single worker can inject 250-350 trees in nine hours, depending on if the trees are currently bearing fruit.

The initial field trials of the FlexInject treatment have shown treated trees having improved health and biomass. Additionally, treated trees show a up to a 60 percent decrease in fruit drop.

The injection process starts with drilling into the tree trunk one inch just above the soil line. The FlexInject applicator is inserted into this hole, allowing the tree to uptake the OTC-HCI product into its vascular system. Once completed, the device is moved to the next tree to repeat the process. Trees can be treated once per season, after harvest, and up to 180 days before harvest. This window is utilized to minimize the risk of chemical residues in the fruit.

On October 28, the Florida Department of Agriculture and Consumer Services granted ReMedium TI a special local-need registration. Tom Johnson, the chief executive officer of TJ Biotech, says ReMedium TI has seen a "broad acceptance across the industry."

TJ BioTech's initial projections were that up to 100,000 of the FlexInject units would be available in the first quarter of 2023. As of the end of February, they have exceeded these projections with 119,000 units already available for growers, and production will continue so that any interested grower should still be able to invest in the ReMedium TI treatment for their groves.

"We are very pleased to bring ReMedium TI to the market," Johnson says. "We believe this is a viable treatment for greening, and we’re grateful to be a part of this scientific advancement."