Proactivity is always better than reactivity. In much the same way, a plant with a strong immune system has a better chance of defending itself than a plant relying solely on external pesticides.

Elemental Enzymes screened more than 40 unique combinations of peptides and antimicrobials in field trials to find the one that incited the best immune response against Citrus Greening. The company then used the selected peptide to develop its proprietary technology, which the U.S. Environmental Protection Agency approved for federal registration in 2023. Elemental has licensed its peptide technology to industry partner, Nutrien, for the foliar spray Aura Citrus, which recently received approval for use in Florida citrus groves.

Stacie Schumer, Global Product Manager with Elemental Enzymes, said one of the company’s goals is to focus on plant diseases and other challenges that don’t have solid solutions. Citrus Greening is a prime candidate for study, considering the devastation it has caused. From 2005 to 2023, the orange industry has suffered a 90% drop in production for Florida alone.

Elemental saw how orange growers have struggled to mitigate Citrus Greening with little success. Researchers wanted to apply Elemental’s proprietary plant-amplifying technology to battle the pathogen more effectively. “We won’t claim to cure it,” Schumer said. “But Aura Citrus, featuring Vismax technology, is an additional tool to help those growers to prolong their trees’ longevity and production capability.”

Nutrien’s production subsidiary for chemistry and innovation is Loveland Products. As a marketing manager at Loveland, Elizabeth Parker manages herbicide and fungicide portfolios. She described how Citrus Greening exponentially weakens a citrus tree, making it more susceptible to other opportunistic diseases.

In trials, Aura Citrus has shown that its formulated peptides awaken and arm a tree’s natural defense system without the “energy drag” that SAR-inducers (systemic acquired resistance) tend to pull from the plant. While SAR-inducers also activate plant defenses, this typically comes at the expense of energy stores the plant would otherwise use for growing and producing fruit.

Applying Aura Citrus results in a tree that is defended and more stable. A treated tree is also better able to retain quality fruit because it can use more of its “fuel” that way. “A defended plant that does not take additional energy to defend itself can maximize its other energy systems required for optimal yield, quality, and everything else those citrus growers are really trying to gain at the end of the season,” Parker noted.

Schumer said that in a set of Florida trials conducted over three consecutive years, Aura Citrus-treated trees improved yield by an average of 23%. Parker added that trees can retain their fruit better since they are not panicking with disease pressure and dropping fruit to save themselves.

“In the trials where we have applied the product multiple years in a row,” Schumer explained, “Aura Citrus continued to improve over the growers’ standard program at each harvest.” Application is best done each spring and fall flush when the tree’s receptors are most responsive to the peptides in Aura Citrus.

Aura Citrus is recommended for foliar application at a rate of 100-130 gallons per acre with a non-ionic surfactant such as Nutrien’s Liberate®, which Parker said is a gentle medium for facilitating activation of as many peptide receptors as possible. She noted that many citrus growers are moving to tree injection with their inputs, including fungicides targeting Citrus Greening and other pathogens. This empowers the tree to attack invaders while defending itself, all at once.

Schumer and Parker have worked together in what Parker calls “a huge collaboration effort” to launch Aura Citrus. Elemental and Nutrien have been able to identify and focus their reach to those in most need of the technology. Ultimately, the collaboration is helping producers maximize their return on investment.

The biggest hurdle to reaching these producers is the number of products over the years that have not solved for Citrus Greening losses. Growers do not want to get their hopes up yet again until they see efficacy in action. Elemental and Nutrien are sensitive to that. “We want to make sure that they understand this is a tool, and that we’re not over-promising,” Parker said, echoing Schumer’s earlier point. “Overall, though, I think growers are being very receptive, and there’s a lot of talk about what this can do.”