STORAGE SCALD - PRESEOT STATUS OF CONTROL MEASURES 



At the New England Apple Storage Seminar on April 21, a discussion of 

 storage scald led by Dr. R. M. Smock of Cornell, Dr. Vlad Shutak of Rhode Island 

 University and the author made it possible for those in attendance to get some 

 idea of where we now stand on this problem. Here are some of the important points 

 that were brought out; 



1. The past season with its hot weather jusc prior to harvest was one which 

 apparently caused many varieties to be very susceptible to scald. 



2. The material Santoquin when used at 1000 to 2000 ppm as a preharvest spray 

 failed to give commercial control on Cortland and Mcintosh. Even diphe- 

 nylamine (DPA) was not as effective as it has been in the past. 



3. Attempts to control scald by manipulation of the nutritional status of 

 the tree have not been successful. 



4. Scald on cold storage Mcintosh is invariably much more serious than it 

 is on CA Mcintosh if both lots are harvested at the same time from the 

 same trees, stored promptly after harvest and stored for the same length 

 of time. 



5. The key to scald control on CA Mcintosh seems to be related to harvest 

 date (much more scald if picked late) and quick cooling after harvest . 



The importance of picking Mcintosh for CA storage on the early side and cool- 

 ing them within 24 hours of harvest can hardly be over-emphasized. Recent data 

 indicate that if this is done, scald control on CA Mcintosh can be obtained with- 

 out having to rely on special wraps, chemical sprays or dips. However, scald 

 control on cold storage Mcintosh and other varieties, regardless of whether they 

 are cold or CA stored, is often impossible by such a simple procedure. 



The data shown in the following tables illustrate these points. 



Table 1. The influence of picking date on the percentage of total scald on 

 cold and CA stored Mcintosh and Cortland. 1959-60. 



Firmness (lbs.) Per cent Scald 



After 7 days at room temp . 



Storage Picking at harvest 



Conditions Date Mcintosh Cortland Mcintosh-*- Cortland 



320F in air 9/9 16.4 18.6 81.4 21.3 



9/16 16.1 17.4 33.1 77.1 



9/23 15.4 16.8 29.5 95.1 



9/29 14.2 15.8 45.3 97.5 



32-360F in air 9/29 14.2 15.8 71.1 100.0 



CA-38°F 9/9 16.4 18.6 2.0 40.9 



3% 02/5% CO2 9/16 16.1 17.4 1.2 32.5 



9/23 15.4 16,8 4.8 43.3 



9/29 14^2 15,^8 44.1 33.2 



^Removed from storage in April, 1960. 



Tlemoved from storage in March, 1960. 



