Staden (157) reported that in 1956 and 1957 Jonathan spot was limited by 
dipping fruits in diphenylamine, but that the results could not be confirmed 
the following season. Padfield (124) found no benefit from the use of diphenyl- 
amine in preventing Jonathan spot. 
Martin, Lewis, and Cerny (98, 99) state that in the absence of other 
disorders there was a positive intercorrelation between percentage Jonathan 
spot, mean fruit size, and mean seed number both within and between trees. In 
one fruit size group on a tree, fruits with Jonathan spot had a higher mean 
seed number per fruit than sound fruit, and seed germination was greater. With- 
in trees, if fruit size was controlled to give differing sizes, but with the 
same seed number, incidence of Jonathan spot was not altered. Between trees if 
fruit size was controlled to give fruits of similar size, but with differing 
seed numbers, the incidence of Jonathan spot varied. It is suggested that the 
relationship is due to the effect of seed number on the rate of ripening. 
Dewey (45) reported that Jonathan spot was controlled during 7 months' 
storage of Jonathan apples in controlled atmospheres of 2.5 to 5.0 percent C09 
and 3 percent 05. 
Scald 
(Scald, because of its importance, is discussed in a separate section. 
See page 194.) 
Soft. Scald 
Relatively little new information has been developed on this nonpara- 
sitic disease, Its occurrence is sporadic, even on susceptible varieties like 
Jonathan and Rome Beauty (142). Sometimes it is serious on Delicious apples 
grown in the Pacific Northwest. Soft scald, or deep scald, is worse on large 
apples and in light crop years (39). It is considered a low-temperature dis- 
order, being most severe at 31° to 32°. It seldom develops at storage tempera- 
tures of 36° to 38° F. Several investigators reported that soft scald is most 
severe on later or more mature pickings (39, 58, 59). Ginsburg (59) examined 
fruit from four pickings over a 5-year period and found a high incidence of 
soft scald on the third and fourth pickings when stored at 31°. For these late 
pickings, the extent of soft scald became progressively higher at 3-, 4-, 5-, 
and 6-month examinations. Yet the injury had its origin in the first month or 
two of cold storage. 
Carne (39) and Gerhardt and Sainsbury (58) reported soft scald was worse 
when there was a delay between harvest and cooling. When there was a delay of 
one week at 70° F. before storage at 31°, soft scald was increased over immedi- 
ate storage (58). Gerhardt and Seinabaey found that two conditions were neces- 
sary for soft scald development on Delicious apples: (1) A critical stage of 
metabolism accentuated by delayed storage or advanced maturity and (2) a storage 
temperature of 32° F. or below. If both were present, soft scald was often 
severe. They recommended 8 weeks' storage at 34° for Delicious apples before 
storage at 31°, if the fruit was susceptible to soft scald. However, with good 
handling and optimum maturity Delicious apples can be placed directly at 31°. 
Gerhardt (unpublished) controlled soft scald in Jonathan and Delicious apples 
by packing them in sealed 1.5 mil polyethylene liners. 
178 
