r 
UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 1118 
Washington, D. C. 
PROFESSIONAL PAPER 
January 26, 1923 
CITRUS SCAB: 
ITS CAUSE AND CONTROL 
By 
JOHN R. WINSTON, Pathologist 
Office of Fruit-Disease Investigations, Bureau of Plant Industry 
CONTENTS 
Economic Importance and Distribution of 
Citrus Scab 1 
Species and Varieties Attacked 3 
Description of the Disease 3 
Review of the Literature 5 
The Causal Organism 8 
Pathological Anatomy 12 
Dissemination of the Causal Fungus ... 12 
Conditions Influencing Infection 13 
Page 
Growth Habits of Grapefruit 20 
Disease as Influenced by the Stock ... 21 
Adaptation of the Fungus 21 
Inoculation Experiments 22 
Spraying Experiments 27 
Commercial Control 30 
Summary 34 
Literature Cited 37 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1923 
