Issue link: http://read.dmtmag.com/i/105709
How could Promalin increase fruit set when we couldn't find any live ovules after the first freeze? Aren't seeds needed to ensure good fruit set and to keep the fruit growing normally? While fruit on the treated trees grew to a normal size and shape at harvest, they had one distinguishing feature—they were largely without seeds, or parthenocarpic. It seems that Promalin increased fruit set and yield by stimulating the retention and growth of fruit that would otherwise have dropped due to the absence of viable seeds. Promalin did not elongate the fruit, but Rome does not have pronounced calyx lobes, so it was not expected. This is not to say it wouldn't elongate fruit of other cultivars. Fruit with few or no seeds may not be suitable for long-term storage, since they may be more likely to develop physiological disorders such as bitter pit. We did not carry out poststorage evaluations in our study. given how low the temperatures dropped. Applying Promalin five hours after freeze events on two consecutive mornings during full bloom increased fruit set and yield by stimulating parthenocarpic fruit development. Similar fruit set and yield responses to Promalin frost-rescue treatments were observed in separate studies in New York in 2012. Fruit set and yield were partially recovered by Promalin, but still only around 25 percent of a full crop. Then again, the minimum temperature during Development stage Critical temperature in °F 10% 90% kill kill The positive effect of Promalin that we observed in this study was surprising, Orchard-Rite® Wind Machines • www.orchard-rite.com "Orchard Rite Service is second to none." "We're real believers in the Auto Start option." Steve Nunley 15 2 Green tip 18 10 Half inch green 23 15 Tight cluster 27 21 First pink 28 24 Full pink 28 25 First bloom 28 25 Full bloom 28 25 Post bloom The bottom line Silver tip 28 25 SOURCE: USDA/WSU Extension Bulletin 0913 (1998) each freeze event was extremely low. To have a positive response at temperatures this low was encouraging, and begs the question what sort of response might we have seen if the freezes were less severe, i.e., in the 28° to 32°F range? There are several other questions regarding the use of Promalin as a frostrescue treatment that need to be answered. First, is the treatment only effective if freeze events occur during bloom, or are they also effective during the pink or postbloom stages? Second, how long after a freeze can Promalin be applied and still have efficacy? Can application be delayed until 24 or 48 hours after a freeze and still have an effect? Unfortunately, attempts to answer these questions will have to wait until the next time we get a spring freeze, which may not happen for many years— hopefully! If you need apples to sell and are not concerned about keeping the fruit in storage for too long, then, yes, our results in 2012 suggest that Promalin might be used as a (partial) frost-rescue treatment. • A s the operations manager for Pride Packing, I am responsible for managing 2,800 acres of orchard under 260 wind machines. Of that, approximately 1,000 acres are in stone fruit with the remaining acreage in apples and pears. From November to February, we can deal with arctic events that will take our temperature into the single digits—and even subzero. I really don't think it's possible to grow stone fruit economically in the Yakima Valley without wind machines. This last year, we would not have even had an apricot crop without them. All of our wind machine purchases since 1982 have been Orchard-Rite. In the wintertime, when we're starting these machines, the temperatures are usually single digits to subzero. We depend on—and have complete confidence in—our Orchard-Rite® Wind Machines and the service we receive. We still have the first Orchard-Rite® Wind Machine we ever bought! We're real believers in the Auto Start option. We order Auto Start on all our new machines. To date, we've retrofitted about 50% of our old machines, and plan to put the Auto Start on the remaining machines. Steve Nunley, Farming Operations Manager Pride Packing, Wapato, Washington Get the Orchard-Rite® story from your nearest representative: 1615 W. Ahtanum • Yakima, WA 98903 • 509-248-8785, ext. 612 For the representative nearest you, visit our Web site: www.orchard-rite.com 38 FEBRUARY 1, 2013 GOOD FRUIT GROWER Pear committee nominations N ominations for a grower position on the Fresh Pear Committee of federal Marketing Order 927 will be taken during the Hood River Winter Horticultural Meeting at the Hood River Inn, Hood River, Oregon, on February 6. The position, which expires June 30, is currently held by Mid-Columbia grower Rod Laurance, with Gordy Sato as first alternate and Ron Rivers as second alternate. The Fresh Pear Committee is responsible for collecting assessments for research, promotion, and advertising of pears. Names of nominees will be submitted to the U.S. Secretary of Agriculture for official appointment. Committee members serve two-year terms. www.goodfruit.com