Growers Continue the Battle Against Citrus Greening
17 June 2021 The assessment is blunt, bordering on scary. “Citrus greening is basically on every farm in Florida. And it seems like it’s going to be endemic, now,” says Landon Bunderson, Chief Science Officer, Aqua-Yield. “It’s just going to be there, and we’re going to have to deal with it.”
Citrus greening has been around for about 100 years, but it’s only been in Florida since about 2005. There is no cure for the disease, only treatments that slow the effects. Also known as Huanglongbing (HLB) or yellow dragon disease, it is transmitted by the Asian citrus psyllid (Diaphorina citri Kuwayama or ACP). The disease first appeared in Asia and more recently growers throughout the Americas and Africa have joined the battle. The psyllid was discovered in Florida in 1998, but confirmation of the first infection took seven years.
While no solution exists, growers have tried a variety of solutions including ripping out acres of citrus groves and replanting. As yet, all treatments offer only temporary respite until the psyllids find the new trees or slow the progression of the disease.
“About twice a year, some researcher will come out with a study that says: ‘Oh, you know, increase the zinc levels or elevated copper levels or this concoction of bacteriacide is what’s going to help,’ ” Bunderson says. “But they used to steam treat the trees. I don’t think anybody is steam treating their trees anymore.”
Growers may have turned away from steaming their trees, but that doesn’t mean they’re without other treatments.
“Growers are using all the tools available from trying to derive new genetics within their citrus from rootstocks all the way through looking at different means to control that vector insect,” says Ryan Bond, Senior Director of Innovation and Research and Development, Nutrien Ag Solutions.
“It’s just wreaked havoc for Florida citrus industry at large since 2005,” Bond says. “So, the disease incidence as basically scaled up to 100%. The actual citrus production has been reduced by 40%, and the lifespan of the groves have been reduced dramatically as well.”
Nutrien Ag recently announced partnership with Elemental Enzymes, an agricultural biotechnology company, for a peptide-based biochemical pesticide to combat fungal and bacterial diseases. According to the company, “The biochemical peptide-based product, delivered as a foliar spray or trunk injection, is currently under review by the EPA. The specific peptide, containing Vismax technology, increases yield and accelerates the recovery of trees infected with the pathogen that causes citrus greening.”
One of the reasons HLB is so devastating is that the tree doesn’t recognize the bacteria within its receptors that would trigger any natural defenses slowing the disease. The Vismax technology uses those receptors to signal the plant to trigger its defense response, “We’re seeing up to a 96% drop in bacterial counts,” Bond says,
Despite a variety of treatments, the situation in Florida remains serious.
“We’re at the bottom in Florida,” Bunderson says. “We’re at the bottom and the industry is on the brink. They’ll have to decide whether or not, or we must bail out the citrus industry in a big way.”
The industry and government have spent billions of dollars already looking for solutions. Despite that, Florida is no longer the only market hit by the debilitating infection. California has seen its share in the past few years.
“It definitely is sneaky; it has kind of a slow build,” Bunderson says. “It’s a multi-year infection, where you get infected one year and you don’t really notice it. In the second year it spreads further, and you don’t really notice it, and then sooner or later it hammers you.”
Until a solution is found growers must focus on mitigating the effects. One way is to improve the way the existing solutions are delivered.
Aqua-Yield, for example, does not offer a solution of its own. What the company does provide is a means to deliver others’ products more effectively. “We don’t say we have a cured citrus greening, but if you have a cure, we can get it to be absorbed more quickly and efficiently,” Bunderson says.
He goes on using an analogy to explain how the company’s offering works.
“The nanoparticles that we use are absorbed rapidly and with higher efficiency than traditional fertilizer additives can do,” Bunderson says. “A nanoparticle is like a cattle truck. You load a whole bunch of fertilizer into that cattle truck a whole bunch of cows and you drive it into the plant. Now, if you can deliver lots of cattle trucks into the plant your net result can be an increase in absorption and that’s what we’re doing with our nano technology.”
Get The Newsletter Today!
