Issue link: http://read.dmtmag.com/i/681909
www.goodfruit.com Good Fruit Grower JUNE 2016 27 ONLINE For more on how to grow WA 38, a WSU summary of WA 38 characteristics and growing tips can be found online at bit.ly/WA38characteristics, or visit the "How to grow Cosmic Crisp" article in the July 2014 issue of Good Fruit Grower at goodfruit.com Generally, the click system is resulting in better bud breaks the following year, but it's more effective in vigor- ous conditions, Musacchi said. However, in a V system, because the trees are planted closer together and are less vigorous, the effects were not as evident, because the length of the branches is shorter. In addition, a mechanical pruning trial at the Prosser, Washington, site is showing promise. Mechanical prun- ing cuts off the tips of branches, thus removing their inherent apical dominance, and helps to stimulate bud break closer to the trunk, or axe, of the tree and minimize blind wood, Musacchi said. Researchers mechanically pruned for the fi rst time last year, then did so again in February. The result: Every cut is resulting in one, two or three buds close to the axe, minimizing the blind wood and ensuring short limbs that improve fruits' exposure to sunlight. Mechanically pruning also prepares a fruiting wall for mechanical harvest in a couple of different ways, Auvil said. Eliminating longer fruiting limbs from rows reduces the potential for damage by limbs that could be sucked into a vacuum harvester, damaging fruit that enter the machine when a limb is in the wrong place. "The other really, really big advantage for the robot- ics format, particularly for the bi-ax system, in looking at mechanical pruning, is the uniformity of color and maturity," he said. Pollinizer reminder Researchers are also reminding growers who intend to plant WA 38 to remember to order their pollinizers. Growers should strive to get two different pollen sources distributed in each block — every 30 feet for every row — such as a Mount Everest and a Snowdrift, or midseason commercial apple varieties, such as Red Delicious, Golden Delicious, Granny Smith or Cameo, Auvil said. • Musacchi recommends notching and girdling just as deep as the bark and phloem to reduce blind wood. He says bending tends to result in two to three more nodes of blind wood than clicking- type pruning methods. "Honestly, the girdling did extremely, extremely well. There is no blind wood through all the length of the fruiting wall." —Stefano Musacchi