172 
Journal of Agricultural Research 
Vol. XXIV, Na a 
Owing to the lack of necessary equipment, it was impossible to measure 
the exact effect of the tent and black bags upon ^e light intensity. 
Nevertheless, it is thought that the light exclusion as such is negligible, 
since it had little or no effect upon the amount of browning as shown by 
the figures of Table V. The number of foggy days might, of course, 
exert an indirect effect by influencing the temperature. 
The effect of the tent and black bag upon the temperature, howeiVer, 
was very striking. The mean daily temperature at the core of the bagged 
fruit, as indicate by self-recording thermometers, was from 2.5° to 5.5^ C. 
higher than that of apples normally exposed. In the case of the tented 
tree, a lower mean temperature was maintained by the shading and lack 
of free circulation of the air. Here the temperature, as recorded by 
acctuately regulated thermograph instruments, was found to be from 2^ 
to 4.5® lower than that for a similar position in an adjacent untented tree. 
The fruit from the tented tree, the bagged and the normally exposed 
fruit from the same trees, and fruit from two adjacent trees for control 
were harvested at the first pickings of the 1920-21 season. All the lots 
and controls were stored under identical conditions at o® C. The results 
of these experiments are given in Table IV. As the fruit of the two 
pickings behaved similarly, only the averages are given in the table. 
TabIv^ IV .—Effect of orchard temperature upon internal browning 
Treatment. 
Condition of fruit at end of storage 
period, Apr. i. 
Nor¬ 
mal. 
Trace. 
Slight. 
Mod¬ 
erate. 
Severe. 
Fruit placed in black bags where temperature of 
appl^ was approximately 4® C. above that of 
Per 
Per 
Per 
Per 
Per 
cent. 
cent. 
cent. 
cenU 
cent. 
fruit in open. 
95 
5 
0 
0 
0 
Fruit normally exposed. 
Fruit from under tent where temperature was 
30 
35 
25 
10 
0 
about 3.5® C. below that in open.. 
5 
15 
40 
35 
5 
The figures of Table IV show a very definite relationship between the 
orchard temperature and internal browning. A daily mean temperature 
of 4® C. above the normal temperature of the orchard practically pre¬ 
vented the browning, while a mean temperature of 3.5® below the nor¬ 
mal mean orchard temperature greatly increased the amotmt of brown¬ 
ing over that which occurred in the normally grown fruit. 
This relation between orchard temperature and the amount of brown¬ 
ing becomes more impressive when the temperature records of this 
valley are compared, for the years of severe and of moderate or no 
browning for this region, with the temperature records of other dis¬ 
tricts where this variety of apple grows satisfactorily and where the 
browning is not a problem. The graphs in figure 2 represent the mean 
temperature for June, July, August, and September for the Pajaro 
Valley, Calif.; Albemarle Coimty, Va.; and Rogue River Valley, Oreg. 
If the record for the Pajaro Valley is considered, it will be seen that in 
1908 and 1914, years in which very heavy losses through internal brown¬ 
ing occurr^, the mean temperature for these four months was very low. 
For 1909, 1910, 1915, and 1916, when the mean temperature for these 
