For its size, the microscopic cuticle surrounding fruits and vegetables is significantly protective. As researchers peel back their understanding of this layer, the positive implications continue to grow.

Oregon State researchers developed SureSeal technology over a decade ago to protect cherries from cracking because of rain. The technology seals the microscopic cracks that can develop as cherries and other fruit grows, protecting it from cracking and exposure to various pathogens.

Cultiva, a company based in Las Vegas, Nev., was founded based on this technology. Company founders at the time viewed it as a revolutionary way to protect cherries from cracking in the rain.

“We saw the results from this technology in cherries and the potential it had,” said Brian Tipton, director of business development at Cultiva.

All-natural product

Cultiva was formed in response to the SureSeal technology developed at Oregon State University after studies there showed it did well to protect cherries from being destroyed by rain.

According to Tipton, Cultiva licensed the world rights to the technology, which continues to show promise in a host of crops currently being studied. The company continues to peel back the proverbial onion layers in what the technology can do through partnerships with universities in the United States and abroad.

Cultiva calls their product Parka. They produce it from their headquarters in Las Vegas, Nevada, and market it worldwide. The liquid material is hydrophobic, permeable, meaning it allows continued transpiration and gas exchange, and is tank-mix compatible. It protects fruit crops by sealing the microscopic cracks that can develop in the cuticle, a thin membrane that surrounds all above-ground plants.

“Because we’re all natural, we’re exempt from tolerances; we don’t need an EPA number,” Tipton said.

Nevertheless, Tipton said the company has fought the urge to promote it as a be-all for other crops until the company could show scientific proof that it works beyond cherries. That is the point of various research projects around the world in a host of crops.

Some cherry farmers in the Pacific Northwest who also grow apples began experimenting with it on their own to protect apples from russeting, Tipton said. Russeting is a process where the cuticle on the apple has microcracking, leading to abnormalities on the skin of the fruit that leaves a brown tint on the skin.

As the apple farmers began to see success in their spray treatments, thoughts began to grow that the technology could have farther reaching impacts.

“That made us think that this has more potential than just cherries and cherry cracking,” he said.

Ongoing research

Researchers in Spain and the United States are finding success with the technology in various crops. Apples, blueberries, cherries, citrus, grapes, nuts, pears, peppers, strawberries, tomatoes, and olives are showing positive results from Parka treatments. At a hosted meeting in Las Vegas, researchers from Cornell, UC Riverside, and Spain explained their ongoing work with the technology.

Jocelyn Rose, director of the School of Integrative Plant Science at Cornell University, said early work in fruit quality may have had a misplaced focus as researchers sought to slow fruit deterioration. Since then, his work has transitioned to studying the plant cuticle and trying to understand how it works.

Plant cuticles must expand and remain intact as the fruit grows, Rose said. Scientists are finding that these thin layers to be elastic, with the ability to repair themselves. But not always.

“Most plants most of the time do that extremely well,” he said of their ability to self-repair. “We’re interested to know how they do that, but then of course sometimes they don’t, and so in that case we want to understand why and is there something we can do about it.”

Some of Rose’s fruit biology work includes tomatoes. Fascinating technology allows scientists to study just those outer cuticle layers and create 3D imagery to better understand cell tissues.

Ashraf El Kereamy, director of the University of California’s Lincove Research and Extension Center near Visalia, is doing similar work in table grapes and citrus. He is finding that cuticle development in citrus could improve cold tolerance in the fruit.

Work on cuticle development in olives was also reported during the Las Vegas meeting by Isabel Laura, a researcher from Spain.

Future studies

Tipton said Cultiva wants to expand its understanding of plant cuticles in leafy greens, which he surmises could be a game changer for the produce industry. Still, researchers and Cultiva representatives say the more they learn of the cuticle, the more questions they have, and the more studies they realize are needed to understand the complexities of the microscopic layer.

Meanwhile, farmers at the Cultiva meeting suggested that they continue to find success in various specialty crops in the West, such as citrus, cherries, and stone fruit.

Though Parka boasts naturally occurring compounds, and thus does not require an EPA label according to Tipton, the company cannot yet market this for organic use because it still requires organic industry certification from the Organic Materials Review Institute (OMRI). The lack of an EPA label has also made it somewhat difficult for registration in Europe and other countries “because we don’t fit into any category,” Tipton said.

The good news in this is there is no minimal risk level, or MRL, for Parka, meaning growers can successfully use it shortly before harvest. It is said to leave no visible residue on crops, unlike other protective layers used by growers.