Since arriving in Florida in 2005, citrus greening has wreaked havoc on U.S. orange supplies, with production declining 95% in 2025 since its pre-disease peak. Nearly 20 years later, Maryland-based biotech company Silvec is joining the fight to restore Florida’s citrus industry thanks to EPA registration of its RNA-based therapy delivery technology.
Launched in 2019, Silvec was co-founded by brother and sister Rafael Simon and Anne Simon, company CEO and chief scientist, respectively. Anne Simon wanted to revolutionize agricultural treatments by using modified viruses to make plants produce specific proteins to fight diseases, Rafael Simon, told AgNavigator.
Silvec uses an RNA-based delivery system of a benign version of the citrus tristeza virus that elicits plants to produce an antimicrobial peptide called defensin, which is helpful in fighting diseases like huanglongbing (i.e. citrus greening).
The strain of the virus was first developed by U.S. Sugar subsidiary, Southern Gardens Citrus, which was then screened for the peptides that were most effective in treating citrus greening.
“This had been done forever in the lab but had never been done commercially because these processes were all very unstable, and there were all kinds of trouble with being able to apply these to different plants,” Rafael Simon elaborated.
He added, “[Anne] had come up with ideas about how to actually use this on a commercial basis to make sure how it’s engineered is stable and how you can develop all the antipathogenic agents to properly target all the different diseases.”
While the tech is applicable to a host of disease and pest pressures, Silvec focused on citrus greening first given the extent of the disease’s impact on Florida producers, Rafael Simon explained.
“We decided, let’s go and start with the most difficult problem that we could possibly find, which was citrus greening,” Rafael Simon said. “We can use our technology across pretty much any type of agricultural disease, any type of crop, but as a start-up, you have to pick one. And on the one hand, you pick a hard one; that makes it hard. But on the other hand, you’re also hitting the biggest pain point.”
Citrus greening: A persistent challenge for global supplies
With EPA registration received, Silvec is working to commercialize its technology and expects the first trees inoculated with its treatment to be available in 2028, Rafael Simon noted.
Unlike biotech companies that rely on large fermentation capacity, Silvec does not require the same manufacturing footprint, Rafael Simon explained. Instead, the start-up works with nurseries to inoculate a mother tree with the treatment, which then can be used to harvest buds that are then planted into other citrus trees, transferring the benefits in the process, he added.
“Viruses exist by tricking their hosts to replicating them and providing proteins that they need — that’s every virus in the world. ... By us inserting a little sequence in there, the virus now tricks the tree to produce the antimicrobial peptide, which is the treatment for the disease, but the tree is actually producing it. So, the scale-up costs are pretty minimal,” Rafael Simon said.
Silvec’s field trials demonstrate the effectiveness of this approach, but the company does not see itself as a silver-bullet solution to citrus greening, but rather a key tool in restoring citrus yields, alongside other solutions like injecting oxytetracycline into trees, Rafael Simon said.
While the focus is on restoring Florida’s citrus groves, Silvec wants to expand the technology elsewhere in the world, including Latin America where citrus greening is on the rise. Nearly half (47.6%) of orange trees in Brazil’s citrus belt (the state of São Paulo and southwest Minas Gerais) were impacted by citrus greening, per Fundecitrus data.
“The psyllids are there forever, and the psyllids injecting the citrus green bacteria into trees are there forever. That’s not something we’re going to be able to really get rid of. So, no matter what you do to the plant, they are constantly having more of this bacteria injected into them. So, you’re not going to get to a point where the plant is going to be free of the bacteria,” Rafael Simon elaborated.
Silvec readies a Series A round
Looking ahead, Silvec is now gearing up to launch a Series A round to support the commercial opportunity of its technology, Rafael Simon said. Having largely been supported by USDA and the citrus industry, the start-up expects to reach profitability next year and is seeking capital to expand the technology, he added.
“We’re working on these other generations. Some of them are targeting the citrus greening bacteria better, but some of them are going after nematodes, fungus, insects, other viruses, and other bacteria. Everything that is plaguing trees, there are solutions for,” Rafael Simon said.
