JOWL OF AGKCDLTCRAL RESEARCH 
Voi.. XI Washington, D. C., November 12, 1917 No. 7 
EFFECT OF TEMPERATURE AERATION AND HUMIDITY 
ON JONATHAN-SPOT AND SCAED OF APPLES IN 
STORAGE 1 
By Charles Brooks, Pathologist, and J. S. Cooley, Assistant Pathologist , Fruit Dis¬ 
ease Investigations , Bureau of Plant Industry , United States Department of Agriculture 
INTRODUCTION 
As the public becomes more critical in regard to foods, the troubles 
which affect the appearance of fruit but do not completely destroy it are 
brought into greater prominence, both from a pathological and an 
economic point of view. These troubles are of importance not only 
because of their damaging effects on the appearance of the fruit but also 
because of the part they may play in paving the way for the entrance of 
various rot-producing fungi. The present paper is a report on Jonathan- 
spot and scald of apples (Malus sylvestris ), including a study of their 
relation to rot infection and the modifying effects of storage conditions 
and maturity of fruit. 
EXPERIMENTAL APPARATUS 
The apparatus used in the experiments has been fully described in an 
earlier publication (3). 2 The fruit was held in galvanized-iron boxes 
which had a 3-inch air space between them and the outer insulating walls 
of the chambers. The brine pipes were located outside of these metal 
boxes. This arrangement made it possible to keep the air in the inner 
boxes free from the drying effects of the brine pipes and thus to maintain 
higher humidities than could have been otherwise secured. The air in 
the inner boxes was circulated by means of fans. Where high humidity 
was desired, the air was fanned over pans containing water and saturated 
sponges; to obtain lower humidities it was circulated over calcium 
chlorid and lime. A record of the temperature and the humidity was 
kept by means of thermographs and hygrographs placed in the middle 
of the boxes and by wet and dry bulb thermometers in front of the fans. 
1 Studies in Emit Rots and Spots. II. 2 Reference is made by number to ‘ ‘ Literature cited, ’ ’ p.316-317. 
(287) 
Journal of Agricultural Research, 
Washington, D. C. 
kn 
Vol. XI, No. 7 
Nov. 12, 1917 
Key No. G—1:6 
