APPLE SCALD CONTROL WITH "STOP-SCALD " 



It is expected that this fall at least two distributors will have available 

 a chemical material called "Stop-Scald", which can either be sprayed on the fruit 

 just before harvest or applied after harvest as a spray (as the fruit passes over 

 a roller sorter or while it is in a field box prior to storage) or dip after har- 

 vest. The active material in "Stop-Scald" (formerly called Santoquin) is 1,2 di- 

 hydro-6-ethoxy-2,2,4 trimethylquinoline. The material was cleared for use in July, 

 1960 by the Pure and Drug Administration and a tolerance of 3 ppm has been set. 



"Stop-Scald" appeared to be promising for scald control in several states 

 for some varieties since 1955 but during the 1959-60 season the results with it 

 were disappointing in both New York and New England. This was particularly true 

 when the material was applied as a preharvest spray. Also, Dr. Shutak of Rhode 

 Island University and I noted that preharvest sprays of this material left a very 

 noticeable dark, ring-type residue where droplets collected and dried on tree 

 sprayed fruit . 



It is possible that the scald susceptibility of some of our apples was so 

 great last year that no material was capable of controlling this disorder. 

 Diphenylamine, (DPA) which has not been cleared , gave the poorest control it has 

 ever given. Prior to that time DPA had given excellent control if applied as a 

 dip or sprayed on the trees v/ithin 24 hours of harvest. 



Dr. Smock in New York has applied "Stop-Scald" to apples in a variety of 

 ways and his data indicate that running the fruit through a dip tank will yield 

 the best control. Spraying the fruit in or out of an orchard container after 

 harvest is the next best method and tree spraying within 48 hours of harvest is 

 the least effective. Regardless of the method you choose, simply wet the fruit 

 completely and quickly. Fruit receiving the post-harvest dip or spray treat- 

 ment can be stored wet after allowing the surplus emulsion to drain off. Some- 

 times drainage is not complete and fruit in the bottom of a box may set in the 

 liquid for a long time and cause some skin injury at these points. Of course, 

 the amount of "Stop-Scald" used per 100 gallons should not exceed that indicated 

 on the label. If you are interested in trying this material in a limited way, 

 be sure to store comparable apples that are untreated so that the performance of 

 "Stop-Scald" can really be determined. 



It is very apparent that, even if this or some other chemical ultimately 

 acquires general acceptance for scald control, such chemicals are not going to 

 be a substitute for good harvesting and storage practices. For example, scald 

 control chemicals should never be thought of as a way of avoiding the necessity 

 of proper picking maturity and quick cooling for CA Mcintosh. Perhaps scald mi^ht 

 be controlled on apples which are really too ripe for CA storage, were not moved 

 rapidly to storage after harvest or were not cooled quickly but the problem of 

 soft, mealy CA Mcintosh would then take its place. 



Frankly, it is our present belief that scald on CA Mcintosh can be controlled 

 without having to rely on special wraps, chemical sprays or dips. In order to do 

 so, however, means picking Mcintosh at 15 to 17 lbs. flesh firmness (on the early 

 side), storing them within 24 hours of harvest and cooling them to 32-34° F within a 

 few days thereafter. However, scald control for cold storage Mcintosh and other 



