Issue link: http://read.dmtmag.com/i/37334
If the pears are removed from storage too early, they will ripen very slowly and the only way for a warehouse to know when they’re ready to sell is to keep taking samples of fruit out of storage at intervals and trying to ripen them. “It’s a commitment,” Mattheis said. “It’s for fruit that you’re not planning to sell, that you want to hold on to for several “If we could predict the responsiveness and adjust the treatment protocol accordingly, I think you could probably get it right every time.” —Jim Mattheis months. If you get an order and that’s all you’ve got, you’re kind of stuck. There’s no means that I’m aware of to accelerate that process in a really short period.” Mattheis has done tests at storage and at room temperatures and found that the higher temperature gave a stronger response in terms of delaying ripening. D’Anjou MCP is also being used to extend the season for d’Anjou pears and control scald. Packers can potentially save money by treating them with MCP and holding them in regular storage instead of putting them in CA and having to apply a scald control. Research has shown that the combina- tion of MCP and CA has given the strongest response and longest duration of ripening inhibition, Mattheis said. Long-term exposure to CA makes the fruit inherently less capable of ripening. Eric Strutzel at Blue Star Growers, Cashmere, Washington, said his company tried using MCP on d’Anjou pears but won’t treat any more because a significant proportion of the pears it sells are condi- tioned, either before shipment or at the retailer’s distribution center, and the treated pears were difficult to ripen. “We used it once, and when we took the fruit out and ran it through our pre- conditioning program, it took five to six times as long to ripen as untreated fruit and never got ripe to the same degree,” he said. However, Strutzel expects the indus- try will use MCP to lengthen the Bartlett season. If California producers use it to ship pears longer, there will be more over- lap with the Northwest season, putting pressure on Northwest packers to shift their season later also. The increasing size of the Northwest crop could also be a fac- tor, he said. Cookie cutter Brad Tukey, with AgroFresh’s research and development department in Yakima, Washington, said MCP-treated pears do ripen, but they ripen differently from untreated fruit, and fruit in CA storage ripens differently from fruit in regular storage. Results also differ depending on variety. “Apples are very cookie-cutter, but the varieties are different in pears and you have to understand that,” he said. Nate Reed, director of pome fruit research and development at AgroFresh, said that although MCP-treated d’Anjou pears typically come out of storage 1.0 to 1.5 pounds firmer than nontreated fruit, they eventually ripen to the same point. Fruit held for five to seven days at 50°F should ripen well, even without ethylene, he said. “I think one of the theories in the com- mercial world is that a SmartFresh-treated d’Anjou doesn’t ripen. That’s not the case.” Reed said side-by-side comparisons would show that SmartFresh-treated pears do ripen. Though the time frame might not be exactly the same as with untreated pears, it’s not extended to the point of being commercially not feasible. • 14 AUGUST 2011 GOOD FRUIT GROWER www.goodfruit.com The reason MCP-treated pears can look ripe even though they’re still hard is because not every aspect of ripening is controlled to the same degree by ethylene, he said.