EXPERIMENTS ON THE DECAY OF FLORIDA ORANGES. 25 



THE FIRST TEST IN WASHINGTON. 



It also seemed possible that oranges from a vigorous tree might 

 prove more resistant to decay than those from a tree that had been 

 much weakened by crown-rot (foot-rot), even when the rind of both 

 is in about the same condition. In order to open the way for some 

 future work along that line, melanosed fruits were selected from 

 both normal and foot-rotted trees and carefully marked when pack- 

 ing. Ammoniated fruits were taken from vigorous-looking trees. 



The fruit was carefully packed and expressed to Washington, D. C, 

 from Orlando, Fla., on February 28. Owing to unforeseen conditions, 

 it had to be held in Washington at room temperature until March 10 

 before being unpacked to start the experiment. At that time several 

 ammoniated oranges were found decayed, apparently by blue mold, 

 and several melanosed fruits and one bright orange were in the early 

 stages of stem-end rot, as indicated by obtaining PTiomopsis citri 

 from their interior. A number of melanosed and ammoniated fruits 

 were rather soft and flabby. Only the firm ones were used in the 

 expernnent, the details of which are given in Table I. A portion of 

 each type of fruit was sprayed with water by means of an atomizer, 

 and the other fruit was spra3^ed with a suspension of the Penicillium 

 or mold spores obtained from vigorous pure cultures formerly secured 

 from moldy oranges. The mold used seems to be most like Penicil- 

 lium italicum, but at present its identification is uncertain. 



After drying, the fruits were wrapped with ordinary orange wrap- 

 pers and each kind placed in separate covered glass dishes. The 

 fruit was all held at room temperature for three days and then some 

 was transferred to a refrigerator having a temperature of about 15° C. 

 (60° F.). On March 17, or a week after the beginning of the experi- 

 ment, the oranges were all carefully examined for decay, and cultures 

 vrere made from the interior of many of the fruits which seemed to be 

 affected by stem-end rot, although the decay was not of sufficient 

 extent to be certain. All but two of such doubtful ones were found to 

 contain Phomopsis citri. The fungus obtained from the two other 

 oranges proved to be neither Phomoj)sis nor Penicillium, and not having 

 produced its spores as yet in culture it still remains unknown. The 

 relation of Phomopsis citri to stem-end rot was established b}^ 

 Fawcett/ who also showed that the decay is not preventable by 

 the application of a fungicide. 



1 Fawcett, H. S. Stem-end rot of citrus fruits. Florida Agricultural Experiment Station, Bulletin 107, 

 23, p. 9 figs., 1911. 



ICii-. 124] 



