Silver bullet is short lived

Neal Manly said Tiberon was a unique tool to help nurseries produced branched trees for high-density plantings.

Photo by Geraldine Warner

When a plant growth regulator that ­stimulates branching of fruit trees became available three years ago, ­nurseries welcomed it as a silver bullet.

Well-branched nursery trees that produce high early yields are the key to profitability in modern high-density orchards, and ever since apple growers began to demand feathered trees, nurseries have used techniques to overcome the natural apical dominance of trees and stimulate branching.

Traditionally, this has been done either by applying Promalin (benzyladenine and gibberellic acid) or by ­removing the top leaves of the trees in early summer.

In 2000, Washington State University research horticulturist Dr. Don Elfving discovered that cyclanilide consistently stimulated branching without the labor-intensive and costly pinching process. Bayer CropSciences registered the product in 2009 for use on nonbearing fruit trees and marketed the product under the trade name Tiberon.

“It was a silver bullet for getting the kind of trees needed in these high-density plantings to get a quick return on their investment,” said Bill Howell, manager of the Northwest Nursery Improvement Institute. “And being able to do that consistently was a good deal.”

But, to the nurseries’ dismay, Tiberon has been taken off the market after just three seasons of use. Bayer told nurseries that demand was too low for the company to cost-effectively maintain the product.

“This is going to impact not just the nurseries,” said Neal Manly, chief marketing officer at Willow Drive ­Nursery, Ephrata, Washington. “This will impact the quality of the trees and the amount of harvest the growers will get in the second and third leaf. This has implications beyond us wanting to grow a better tree.”

Limited market

Nurseries acknowledge the market is limited, particularly as the product is highly effective at low rates. Howell estimates that the entire Pacific Northwest tree fruit industry has only been using a few hundred gallons a year. But he believes demand for the product would increase if it continued to be available. Tree fruit nurseries across the country and overseas have expressed interest, and it’s possible it could be used for ­ornamental trees, he said.

Bayer actually sells a lot of cyclanilid. Some is formulated with Ethrel (ethephon) and marketed under the brand name Finish for defoliating cotton plants and opening the bolls. But Elfving said Finish could not be used in place of Tiberon because it contains a very high rate of Ethrel that would be toxic to trees. Plus, Finish is not registered for use on tree fruits.

Bayer also formulates cyclanilide with mepiquat chloride in a product called Stance, which is used on cotton to control growth, promote earliness, increase fruit retention, and reduce boll rot. Elfving said he does not know how that combination would affect fruit trees.

Howell e-mailed Bayer to ask if the company would package cyclanilide on a limited or contract basis for the nursery industry during their facility’s slow time, but the response was not encouraging. He said the company appeared to be concerned about liability issues and preferred to focus on proprietary products with better profit potential.

Frustrated

Manly said only a few nurseries have been using Tiberon so far, so the potential market—though not large—could be considerably bigger than it has been.

He said nurseries are frustrated that, after seeing good results with the chemical, they’re not able to use it any more.

“It’s very frustrating from the nursery point of view that we’re not coming to some sort of a compromise or alternative approach to making the chemical available,” Manly said. “We haven’t ever had a chemical that does quite what Tiberon does.

“I think the growers will see a difference in tree quality, unfortunately,” he added, ­noting that Willow Drive had received incredibly positive feedback about the ­quality of the trees since it began using Tiberon.

Pete Van Well, president of Van Well Nursery in East Wenatchee, Washington, said Tiberon was particularly useful for Fuji, which doesn’t naturally branch well, and the nursery used it also on Gala.

“We were real happy with it,” Van Well said. “It worked very well for us.”

Van Well said his own stocks are depleted, so he called various chemical companies to see if any had product that he could buy to use this summer. They didn’t.

The nurseries’ only remaining hope is that some other company will be interested in formulating the product for use in tree fruits, Howell said.

“I’ve contacted one outfit, and they weren’t interested. The volume concerns them. It’s a very effective chemical, and only a small amount is needed to get the job done.”

Cyclanilide is not patented and is advertised on the Internet from a number of sources in China. It was registered with the U.S. Environmental Protection Agency in 1996, and nonbearing tree fruits and ornamentals were added to the label in 2006. The EPA reviews each active ingredient about every 15 years, and cyclanilide is ­currently going through the reregistration process.

Bayer CropSciences did not respond by the magazine’s deadline to questions ­e-mailed by Good Fruit Grower.