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New counterattacks against HLB

invaio hlb tree canister

A new method for treating the ruinous disease huanglongbing (HLB, aka citrus greening) has been approved by the Florida Department of Agriculture and Community Services (FDACS).

HLB is the chief cause for the rapid decline of Florida citrus acreage over recent years. Aac3.pdf (

Recent treatment methods for HLB have focused on trunk injections. But there are concerns about this approach, which could weaken the main columnar support of the tree—an enormous disadvantage when it is carrying hundreds of pounds of fruit. 

The new method has been released by Invaio, a “bio platform company accelerating the leap to nature-positive agriculture.”

“Our Trecise system [a canister] delivers ArborBiotic—a formulation of oxytetracycline—directly into the conductive tissues of the tree” rather than the trunk, says an Invaio source. “Our system uses 90% less active ingredients than conventional injection treatments for equivalent or better efficacy.”

Benefits listed for the Invaio system include:

• Elevated BRIX levels and an average yield increase of 30% after just one treatment 

“• Shortens treatment by 60 days compared to conventional injection methods

“• Eliminates the need for drilling, making it suitable for young and non-bearing trees

“• Closed system design injects active ingredients directly into conductive tissues

“• Requires less application for equivalent efficacy

“• Dramatically reduces risk of exposure to workers and the environment due to misapplication or residue”

“We are on track to make a Section 3 regulatory application for U.S.-wide treatment of HLB in oranges in 2024,” says the Invaio source. 

On another front, scientists at USDA’s Agricultural Research Service have found a way to boost citrus trees’ resistance to pathogens, such as the one that causes HLB. This method utilizes agrobacteria to import disease-resistant genes into the trees.

The researchers had to identify the appropriate HLB-recognition genes, incorporate enough of them to be effective, and design a pathway to introduce them into trees.

One way to deliver the genes is to use agrobacteria.

“Agrobacteria is a microbe that originated in soil, but has been turned into a plant engineering tool,” explains ARS geneticist James Thomson. “Essentially you clone the DNA of interest”—in this case, HLB resistance—“add it to the agrobacteria, then the agrobacteria adds that specific bit of DNA to the genome.” 

Getting this DNA into targeted trees is the next step. “This is all done in the lab through tissue culture,” Thomson continues. “A bit of the original plant is cut into little pieces and mixed, temporarily, with the agrobacteria. The plant pieces are then cleaned of agrobacteria and encouraged to regrow into a whole plant.”

The researchers plan to transfer their technology and knowledge to tree nurseries, where growers will be able to buy them. Thomson says he sees the technology “being deployed in the next several years.”


Richard Smoley, contributing editor for Blue Book Services, Inc., has more than 40 years of experience in magazine writing and editing, and is the former managing editor of California Farmer magazine. A graduate of Harvard and Oxford universities, he has published 13 books.