Good Fruit Grower

October 2015

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20 OCTOBER 2015 GOOD FRUIT GROWER A fter researching this tem- peramental apple variety for several years, Dr. Randy Beaudry has developed a set of guidelines for harvesting and storing Honeycrisp apples. Beaudry is the post-harvest physiolo- gist at Michigan State University. Pressure has been building, slowly, for him and other storage experts to figure out how to store this much-demanded variety longer to accommodate an increase in produc- tion and a lengthening marketing season. Beaudry's protocols, developed with his Ph.D. students Carolina Contreras and Diep Tran, now extend storage up to nine months, maybe a tad longer. The protocols vary depending on whether storage will be in regular air storage or modified atmosphere, and whether or not the apples will be treated with diphenylamine (DPA) or 1-MCP (1-methylcyclopropene or SmartFresh). Honeycrisp has shown itself to be very sensitive to carbon dioxide injury and chilling injury, and apple quality after storage very much depends on the matu- rity of the apples at harvest. The storage protocols start in the orchard. And that's where Beaudry spoke to growers about it—standing in the sun in Ridgeview Orchards, operated by Joe, Al, Dan, and Ryan Dietrich, in Conklin, Michigan, during the Michigan Pomesters fourth annual RidgeFest fruit grower tour this summer. Three essentials Each of the storage protocols starts with the same trio of admonitions: —First, don't try to store apples that are not properly mature. "Harvest at optimal maturity," Beaudry said. That means using the Cornell Starch Chart and harvesting before apples reach 60 percent starch clearing, or read less than 6 on the starch index chart. Apple background color should not have entirely changed from green to yellow. —Second, Honeycrisp apples need to be preconditioned before they are moved into storage. There is still some variation in the practice, between "mild preconditioning" and "intense precon- ditioning," but each involves holding apples at warmer temperatures for a few days before moving them into colder air or CA storage. The mild form is to hold the apples from five to seven days at a temperature of 50° to 68°F to suppress chilling injury for either air or controlled atmosphere storage conditions and CA injury in controlled atmosphere storage. During that period, the fruit should be stored in conditions—vented if necessary—where carbon dioxide levels can't build above 1 percent. "This is especially important for fruit from young trees," Beaudry said. The intense form of preconditioning is to hold the apples at a higher tempera- ture, 70° to 77°F, for a shorter time, three to five days. "This more intense form of conditioning will help protect the fruit Crucial tips to store Honeycrisp Apples Treated properly, stored Honeycrisp can maintain quality nine months and longer. by Richard Lehnert S T O R A G E C O N T R O L S Y S T E M S MICHIGAN · WASHINGTON · 800.887.7994 · STORAGECONTROL.COM A T T E N T I O N D C A U S E R S USE HARVESTWATCH? EXPERIMENTING WITH DCA? Senzytec2 is a biosensor system that quickly and simply measures the production of ethanol as a result of stressing your fruit when experimenting with DCA. e operator can easily test for and verify fermentative processes taking place during dierent storage conditions at very low levels (less than 50 ppm) with no sample pre-treatment required, and see results in under 5 minutes. Developed and tested at an agricultural research institute in Italy, the Senzytec2 is now available for both sales and service in North America through SCS. Contact us today for more information!

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