Circled by more than 75 apple growers and orchard managers, Washington State University researcher Stefano Musacchi took a willowy first-year WA 38 tree in hand, deftly removing spindly branches with a sharp pair of clippers and a single swift click.
Then, he turned the clippers over to growers, giving them hands-on lessons in click pruning, a technique meant to shape year-old trees for controlled vigor, better sap flow and reduced blind wood, improving long-term yields.
Musacchi, Endowed Chair of Tree Fruit Physiology and Management at WSU, led the Nov. 5 pruning tour of Yakima Valley orchards growing the new apple, branded as Cosmic Crisp®. Visiting WA 38 orchards in Tieton, Selah, Zillah and Sunnyside, this first in a series of November tours took in a variety of training systems and rootstocks in young trees.
“We’re removing branches that compete and compromise the growth of the tree,” Musacchi said. “Timing and consistency are key. The goal is to fill up the space with good, productive branches.”
He answered questions, attempted to solve pruning challenges, and demonstrated proper technique for scoring and notching, shallow cuts into the tree’s living bark and phloem, or vascular tissue, to control the flow of hormones and reduce blind wood.
Click pruning was first developed in Europe two decades ago. Musacchi continues to refine the method in partnership with Washington growers.
“I’ve spent all my life learning, and today I’m learning here with you,” he said.
Karen Lewis, WSU Regional Tree Fruit Specialist, stressed the importance of consistently reminding orchard pruning teams of the correct method and purpose.
“Bring your crews together, demonstrate the proper technique, but also tell them why it’s important to do it right,” she said.
More than 5 million WA 38 trees have been planted in Washington. The new variety is the result of a 20-year effort at WSU to develop juicier, better-storing and higher quality apple cultivars for the state’s tree fruit industry.
Pruning tours continue
WSU-led WA 38 Pruning Tours continue Friday, Nov. 9, in Washington’s North Central Region, with tours of orchards in Tonasket, Orondo, and East Wenatchee. Learn more here.