nOn removal from storage ■ Following 7 days at 68 F 







Figure 



2. Scald development following 25 weeks of 32°F air storage of Delicious apples (harvest dates vary). 



lead us to a set of conclusions about the current state of 

 knowledge regarding scald development and control 

 for New England-grown Cortland apples. 



In our studies, we collected Cortland apples from 

 1985 through 1998 at the Horticultural Research 

 Center (HRC), Belchertown, MA. In addition, 

 samples were collected from other sites: Shelbume 

 and Warren, MA (1997), Putney, VT (1996), Durham, 

 NH (1995, 1996, and 1997), Storrs, CT (1995), and 

 Monmouth, ME (1996). Each sampling site provided 

 at least two harvests per year indicated. Fruit were 

 stored at 32"F in air for 20 weeks, and then kept at 68"F 

 for one week, after which scald development was 

 evaluated. (In some years, scald was evaluated both at 

 removal from storage and again after one week at 

 68°F.) All fruit were standard Cortland, i.e. no red 

 sports were used. Fruit were not treated with DP A. 



Cortland and Delicious differ in a very important 

 way in the manner in which they develop scald. Figure 

 1 shows the presence of scald immediately upon 

 removal from storage and then again after one week at 

 room temperature. In most cases, little or no scald was 



present when the Cortlands were removed from 

 storage, but it was present, sometimes extensively, 

 after the fruit had been warmed. In contrast. Figure 2 

 illustrates the performance of Delicious. On these 

 fruit, most scald was present at removal from storage, 

 with only slight increases at room temperature. This 

 means that Cortlands are very deceptive. They may 

 look scald-free at the time of packing but become 

 badly scalded once they warm up. Delicious, on the 

 other hand, do not present this problem. A trip to the 

 supermarket can be instructive. Rarely will you find a 

 scalded Delicious on display, but scalded Cortlands 

 are a common occurrence. Scalded Delicious usually 

 can be removed during packing, but many Cortlands 

 scald after packing. 



For a scald prediction system to be of value, you 

 must have considerable variation in scald development 

 on samples. You can see in Figure 1 that this was the 

 case in our experiments. Some samples developed 

 hardly any scald while others developed a great deal of 

 it. What are the sources of scald variation in Cortland? 



In Figure 3 you see year-to-year variation in scald 



Fruit Notes, Volume 64 (Number 2), Spring, 1999 



