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Apples—leaves and fruit—covered with Surround. Photo by Dick Lehnert

Apples—leaves and fruit—covered with Surround. Photo by Dick Lehnert

Changes to Engelhard Corporation’s patent for Surround (a particle film made from kaolin clay) may open the door for other companies to produce and sell particle films for reducing drought stress in crops, a patent attorney says.

Engelhard filed a patent application in 1997 for “a method for enhancing the photosynthesis of horticultural crops, which involves treating the surface…with an effective amount of one or more highly reflective particular materials.”

The patent, assigned to Engelhard in 2000, lists U.S. Department of Agriculture scientists Drs. Mike Glenn and Gary Puterka and Dennis Sekutowski of the Engelhard Corporation as inventors. A patent gives the holder the exclusive rights to stop others using the invention for 20 years from the date of the patent application.

Engelhard’s patent encompasses a broad range of fine-particle materials, in addition to kaolin, including calcium carbonate, talc, bentonites, clays, pyrophyllite, silica, feldspar, sand, quartz, chalk, limestone, diatomaceous earth, and barites.

Challenged patent

In 2003, Columbia River Carbonates of Woodland, Washington, challenged the patent on the basis that particle films had been used for similar purposes for many years before Engelhard obtained the patent.

Steve Adamson, a patent attorney based in Portland, Oregon, who represents CRC, said that to be patented, an invention must be useful, novel, and unobvious. If there is any “prior art” relating to the invention more than a year before the filing date, a patent cannot be issued. Prior art is the body of existing knowledge about the invention—any previous patent or use of the invention, or any publication about it, such as a journal article.

CRC had found journal articles, predating the patent application, describing experiments in which films were applied to plants to increase yield.

Adamson said people have been applying fine particle mineral materials to plants to increase quality and yield for many years. “People have been doing that for centuries, if not millennia. What CRC did is contact the patent office saying, ‘We found some prior art that was not considered by the examiner in the initial examination of the patent application.’”

After reexamining the patent documents, the U.S. Patent Office concluded that Engelhard’s claims were too broad, Adamson said. The Patent Office said the scope of the patent should be narrowed, and it reissued the patent in March this year so that it covers the application of reflective, fine-particulate materials to plants to enhance photosynthesis specifically by increasing carbon dioxide assimilation, which was not mentioned in prior art.

In a press release, Peter Barrows, Engelhard’s director for crop protectants, described the Patent Office’s decision as a “clear win for all those who depend on Surround crop protection for sunburn and heat stress protection.”

Barrows said the company had invested a lot to bring the technology to growers and was pleased that the U.S. Patent Office has reaffirmed the patent.

But Adamson said he believes it’s a loss for Engelhard, as the company lost some of its rights. Under the initial patent, it didn’t matter how the product increased photosynthesis. Now, the patent only covers increasing photosynthesis by carbon dioxide assimilation. “That’s one real narrow way in which one might use reflective materials on plants,” he said.

The narrowing of the patent means that products that enhance photosynthesis or reduce drought stress in other ways, such as by blocking the leaf surface to keep the leaf temperature in a range where it functions better, would not infringe the patent, in Adamson’s opinion. It means that other companies can market highly reflective particle products for any use that falls under prior art. “Anything under prior art is a 100-percent safe harbor,” Adamson said.

Competing products

Reed Sherar, attorney with Columbia River Carbonates, said CRC had intended to start marketing a product called Microna Shade, “but we never did because we were threatened with litigation by Engelhard.”

Sherar said CRC won’t enter the market yet, despite the change in the patent, because the company believes that the definition of the invention in Engelhard’s patent is still too broad and that CRC can successfully challenge Engelhard’s remaining claim relating to enhancement of photosynthesis through assimilation of carbon dioxide.

“We feel that we can narrow that patent even more, if not eliminate it,” he said. “It’s just going to take a little more digging. We’re not going to enter the market at this time because one can’t take threats of litigation too lightly, especially from huge corporations. We’re not interested in doing battle. We’re interested in seeing that ultimately the growers get the best product for the best price in a lawful manner.”

A kaolin product called Sun Guard, which has been used on fruit, vegetable, and nut crops in California for many years, is being marketed in Washington for the first time this season. Don Aluisi of Clovis, California, said he’s produced and sold the material for 46 years.

In 1964, he obtained a patent for a temperature-control spray, whose main ingredient was silicon dioxide, which formed a protecting coating on the tree as a barrier against the transfer of heat into and out of such crops during extreme temperatures without impairing normal growth. The patent expired after 17 years.

Aluisi said the product he’s selling today is basically made of kaolin, plus some other ingredients, and sells for much less than Surround. He has never been challenged by Engelhard.

Sun Guard has been tested on various crops, including Granny Smith apples, by scientists at the University of California, Davis. Aluisi said until now he’s sold the product only in California, because he had all the business he could handle.

Earlier this year, however, he was contacted by Roger Wilson of Wilson Orchard and Vineyard Supply in Yakima, Washington, at the World Ag Expo in Tulare, California, Aluisi gave him exclusive rights to sell the product in Washington.

Dr. Larry Schrader, horticulturist at Washington State University, developed a film called Raynox for sunburn control. Schrader said that when he launched the product Engelhard claimed that Raynox violated its patent, but WSU argued that it did not because it is made mainly of wax with a very small amount of clay in the formulation. Raynox is manufactured and marketed by Pace International, LLC.

The Washington Tree Fruit Research Commission has tested a number of other films for sunburn reduction, including Eclipse (a calcium and boron fertilizer from D&M Chem, Inc., Yakima, and Fruit Shield (an experimental product from G.S. Long Company, Inc., Yakima).