| UNITED STATES ie 
1 
| DEPARTMENT or AGRICULTURE | 
| 
DEPARTMENT CIRCULAR 409 | 
; 
i 
| Washington, D. C. April, 1927 
eee. Eee ae es EP ss | Co ST A EL ee 
EFFECT OF SPRAYING WITH FUNGICIDES ON THE 
KEEPING QUALITY OF FLORIDA CITRUS FRUITS 
HARRY R. FULTON 
Pathologist 
and 
JOHN J. BOWMAN 
Assistant Pathologist 
Office of Fruit Diseases, Bureau of Plant Industry ! 
CONTENTS 
Page Page 
Major rots of Florida citrus fruits__ 1 | Effectiveness of one and two applica- 
Experimental methods__-______-_____ 3 tions of | Bordeanx-oil_) == 2 8_ == 9 
Single applications of standard Bor- Modified ‘copper ‘sprays_-———= _- 9 
TTR ST ae ee ee ni Dee ee 5 Lime-sulphur sprayse.22= = toe. ses 10 
KIiffects on various rots_________~_- 6 | Prolongation of keeping period_____ 11 
Two or more applications of stand- General discussi0n=* 22 72. Sets 12 
aru Morgemws-O1. 2s fi PUMMATY o. Se eee eS 18 
MAJOR ROTS OF FLORIDA CITRUS FRUITS 
Florida oranges and grapefruits are subject to three important 
rots during marketing. These are blue-mold rot and the two forms 
of stem-end rot. Practically all of the blue-mold rot is caused by 
the olive-green fungus Penicilliwm digitatum, but occasionally the 
blue-green P. ztalicum. is responsible. 
Blue-mold rot develops only after injuries have destroyed the 
naturally effective protective covering of the fruit and is prompt 
in showing up at ordinary temperatures. It can be reduced by 
stopping picking operations in periods of wet weather when fruit 
is tender, by careful handling to prevent injuries to the fruit, by 
1 Until the season of 1925, John R. Winston, then pathologist in the Office of Fruit 
Disease Investigations, Bureau of Plant Industry, was in active charge of the field opera- 
tions connected with this investigation. The writers acknowledge their indebtedness to 
him and to Frederick A. Wolf, Walter J. Bach, and John F. Wootten for very valuable 
help in the conduct of the work. 
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