Feb. 24, 1919 



Apple-Scald 



199 



9i*e^AS 



RELATION OF TEMPERATURE TO APPLE-SCALD 



A rather full discussion of the^ relation of temperature to apple-scald 

 has already been published by the writers.^ The results given in figures 3 

 to 10, inclusive, of this papei' confirm and extend the statements 

 of the earlier report. As in the earlier experiments, the apples were 

 stored in moist chambers and ten or more apples were used in each test. 

 The experiment was started on August 21. 



A study of the figures shows that the optimum for scald production 

 is approached at 15° C. and the maximum apparently reached at 25°. 

 With all of the different 

 varieties tested scald 

 failed to develop at 

 either 25° or 30°. This 

 fact gives evidence that 

 scald is not purely an 

 old-age characteristic 

 and that it can not be 

 mainly due to the ac- 

 cumulation of carbon 

 dioxid, for both the 

 aging and respiring of 

 the fruit are accelera- 

 ted by these high tem- 

 peratures. 



A comparison of the 

 results at 15° and 20° 

 shows that in several 

 cases (fig. 3, 4, 5) there 

 was a shift in the opti- 

 mum as the experiment 

 advanced. Scald ap- 

 peared first at 20° and 

 for several weeks was worse at this temperature than at 15°, but later 

 became decidedly worse at the lower temperature. 



A particular degree of scald usually developed 8 to 12 weeks later at 

 5° than at 15° and several weeks later at 0° than at 5°. Scald was worse 

 at 5° than at 0° in all cases except with the very green Grimes (fig. 3) 

 and fairly green Rome Beauty (fig. 8). 



In all of the above temperature experiments the apples were placed 

 in moist chambers. The relative humidity was practically 100 per cent, 

 the carbon dioxid from i to 3 per cent, and there was practically no air 

 movement. In all of the various experiments and at all of the different 

 temperatures similar apples were held in open containers in an atmos- 

 phere having less than 0.5 per cent of carbon dioxid, a relative humidity 



' Brooks, Charles, and Cooley, J. S. EFFECT OF TEMPERATtTRE, aeration, and humidity ON 

 JONATHAN-SPOT AND SCALD OF APPLES IN STORAGE. In Jour. AgT. Research, v. ii, no. 7, p. 287-318, 23 fig.i 

 pi. 3a-33. 1917- Literature cited, p. 316-317. 



Fig. 3. — Graphs showing the effects of temperature on apple-scald at 

 the end of 4, 6, 7, 9, 13, and 16 weeks. The dotted graph shows the 

 amount of scald that was evident after removal from storage at the 

 end of the given week and holding the apples at 20° C. for 3 days. 

 The apples were Grimes from Vienna, \'a., picked on August 20. 



