276 



Journal of Agricultural Research voi. xxii, No. 



however, has a high optimum temperature, and it seemed highly improba- 

 ble that its growth could be controlled by exposing to high temperatures 

 and that it caused most damage at temperatures around 32° to 40° F. 

 It was possible, however. This point was investigated by Dr. F. V. 

 Rand, of the Laboratory of Plant Pathology, Bureau of Plant Industry. 

 The results of this work are as yet unpublished. The following account, 

 however, is based on Dr. Rand's work. 



Table IV. — Results of storage experiments with Duncan, Marsh Seedless, and Silver 



Cluster grapefruit 



MARSH SEEDLESS 



Sn,VER CLUSTER 



" Controls placed directly in cold storage. 



Cultures were made from the pits and from the tissue of the peel 

 between the pits. Cultures were also made from the peel of cured fruits 

 which had been in cold storage for three months after curing. The 

 results are shown in Table V. 



It is evident from Table V that Colletotrichum was almost univer- 

 sally present in the peel of these Florida grapefruits and that while it 

 is usually to be found in the pit it is just as common in the normal peel 

 of the pitted fruit or the cured fruit. It is, of course, impossible to 

 assert from the evidence at hand that the fungus does not cause the 

 breaking down of the peel. The cold storage might so affect the physi- 

 ology of the peel as to make it susceptible to fungus attacks, while curing 



