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Scald is always a worry during apple storage. We did 

 not have serious scald problems in New England last year, but 

 in many parts of North America scald caused very serious losses. 

 The reason was probably high temperatures during the harvest season- - 

 high temperature shortly before harvest increases the susceptibility 

 of apples to scald. When susceptibility is high, conventional scald 

 control measures may not be effective. If high temperatures have 

 prevailed immediately before harvest, and especially if coloring 

 is poor and you know that your nitrogen levels tend to be high, you 

 should take extra precautions to thoroughly apply scald inhibitors 



at maximum dosage but not above maximumi You should also be 



extra careful with storage management to delay ripening as much as 

 possible, since scald development comes with ripening, and make 

 every effort to market the fruit as early as possible. We have 

 also found that a high calcium level in the fruit can reduce scald 

 development . 



Your fertilizer program can certainly influence your storage 

 problems with apples. In particular, if nitrogen or potassium are 

 quite high in your trees, or if calcium is low, you may encounter 

 much greater problems during storage. The importance of nutrition 

 is dramatically illustrated by a system now used in England to 

 determine length of storage. In this system, samples of apples are 

 collected from each orchard 2 weeks before harvest and analyzed for 

 5 mineral elements. Based on the analysis, the grower is informed 

 of the maximum length of time he can store his apples and still 

 market them cooperatively. A simpler system, based solely on fruit 

 calcium analysis, is also being used for export apples in New 

 Zealand. 



We plan to test the English system this year, but in the ab- 

 sence of a fruit analysis, observation of your fruit can help avoid 

 problems. If your trees have lush, dark green foliage and the apples 

 are large and poorly colored, nitrogen levels are probably high and 

 the fruit should not be stored late. If you see significant amounts 

 of cork spot or bitter pit on the apples, and especially if the 

 fruit are large, calcium levels are probably low and the fruit should 

 not be stored late. In either case you should consider a post 

 harvest dip treatment in calcium chloride (CaCl2). CaCl2 is com- 

 patible with scald inhibitors and fungicides, so the treatment can 

 easily be accomplished if you are dipping the fruit anyway. A high 

 CaCl2 concentration (24 to 32 lbs/100 gal) is essential for success, 

 since most of the calcium is absorbed into the fruit from residues 

 during storage. This high CaCl^ concentration is corrosive and can 

 cause skin injury on the fruit, but injury is much more of a pro- 

 blem in warmer areas, such as Maryland and Virginia, than it has 

 been in New England. 



Postharvest CaCl^ dips have repeatedly been shown to reduce 

 softening and storage disorders of apples, and use of these dips 

 is growing in many apple-producing regions. Research is also cur- 

 rently being conducted in several areas on the infiltration, by 

 either pressure or vacuum, of large amounts of CaCl^ into apples, 

 but many questions remain to be answered about this method. We think 

 that there is much potential benefit to be gained from CaCl2 dips. 



