Australia is taking steps to protect its citrus industry from one of the world's most destructive plant diseases, with promising field trial results emerging from a Hort Innovation-funded research project.

The project focuses on developing citrus trees resistant to HLB (Huanglongbing, or citrus greening), which has caused a multi-billion-dollar reduction in Florida’s citrus industry since it was first detected in 2005.

As a result, production costs for Florida growers doubled as volumes fell by 90 per cent, revealing the massive impact the disease could cause if it made its way to Australia.

However, by introducing a harmless virus modified to include a special defence protein, researchers discovered a way to supports the tree’s immune system and effectively ‘vaccinate’ against HLB.

Hort Innovation General Manager of Production & Sustainability R&D Anthony Kachenko said early results were encouraging, demonstrating the potential of a tailored product specifically designed to protect citrus trees.

“While Australia remains free from HLB, the disease has caused significant damage to citrus industries around the world, resulting in reduced yields, increased production costs and, in some regions, the loss of entire orchards,” Mr Kachenko said.

“By investing in solutions before the disease arrives, Australia is positioning itself at the forefront of global biosecurity preparedness.

“Australia has a unique opportunity to prepare for biosecurity threats before they arrive. This research is creating invaluable insurance against HLB, one of the most damaging citrus diseases globally.”

Rafael Simon, Silvec's CEO, who led the project in the United States, said a single application of the technology could immunise plants without genetically modifying them, providing long-term protection against a wide range of pathogens.

“We know agriculture globally is under unprecedented threat from invasive pathogens and pests. It’s critical we prepare and protect growers from diseases that are not yet present, and at the same time develop tools to enable affected growers to continue to produce food,” Dr Simon said.

“The promising results we're seeing from our field trials demonstrate the potential of innovative technologies to help safeguard the future of Australia's citrus industry.”

A key focus of the project was the development of a tailored disease-resistance platform for Australia to eventually support commercial nursery systems. In the future, growers may be able to purchase trees more resistant to HLB and other pathogens, providing an additional layer of protection for the industry and strengthening long-term resilience.

The research cemented Australia’s position as a leader in preparing for and responding to emerging horticultural biosecurity threats, with Hort Innovation acting to ensure local growers had access to cutting-edge technologies and solutions.

“By investing now in next-generation disease resistance, the industry is building the tools and knowledge needed to protect citrus production, maintain market confidence and support grower profitability for decades to come,” Dr Kachenko said.

Citrus Australia CEO Nathan Hancock said the peak industry body supported early investment in HLB preparedness, but stressed the need for robust evidence before any new technology was adopted.

“Australia has the advantage of being able to prepare for HLB before it arrives. Investing in research now gives our growers the best chance of having effective management tools available if we ever need them,” Mr Hancock said.

“This is important research, and we support Hort Innovation investing now to explore technologies that could help protect the Australian citrus industry from HLB.

“The early research is encouraging, but we need to be careful not to get ahead of the evidence. We want to see robust, transparent results over multiple seasons, together with appropriate regulatory scrutiny, before determining what role this technology might play for Australian citrus growers.”