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Vol. XXIII Washington, D. C., March 3, 1923 No. 9 
GRAY MOLD OF CASTOR BEAN 1 
By George H. Godfrey* 
Pathologist , Cotton , Truck , and Forage Crop Disease Investigations 
INTRODUCTION 
The castor bean (Ricinus communis L.) has had a unique history as 
a commercial crop in America. From i860 to 1900 it was a common 
crop, particularly in Oklahoma, Kansas, Missouri, and Illinois (7, p. 
295 )/ Climate and soil conditions in some parts are highly suitable 
for its more general culture, as witnessed by the thousands of dooryard 
clusters of plants that may be seen throughout the Southern States. 
Furthermore, there has always been a sufficient home market for the 
product, the United States consuming annually something like a million 
bushels (13). Nevertheless production had gradually dropped off, and 
for years previous to the World War, the crop was grown only sporadic¬ 
ally in limited areas in the South. The one factor which has prevented 
the crop from being a success in this country is an economic one, namely, 
inability to compete with foreign producing sections. The bulk of castor 
beans used in this country have for years come from India, where pro¬ 
ducing costs are low. 
In one year, and for one year only, this state of affairs was completely 
changed. In 1918 large areas were devoted to the crop all the way from 
South Carolina to California, along the southern border. Something 
like 70,000 acres were planted altogether. The reason was, obviously, 
the great war, and the purpose, to provide the necessary lubricant, castor 
oil, for the rotary engines used in a part of the immense new fleet of 
aeroplanes. The usual source of supply, India, was virtually cut off 
by the war-emergency need of practically all shipping for other purposes. 
Consequently it was necessary that the supply be produced in this 
country. The first need was, of course, for an adequate amount of seed. 
Sufficient seed did not exist in America. This problem was met eventu¬ 
ally through the activities of the War and State Departments, by having 
a shipload of castor beans from Bombay, India, diverted from England, 
where it had been destined to be made immediately into oil. The seed 
was distributed by an organization perfected by the War Department 
to farmers in the Southern States who agreed to grow them for a guar¬ 
anteed price per bushel. 
Early in the year before this unusual crop was planted a thorough 
search in the literature was made to determine to what diseases, if any, 
1 Accepted for publication Aug. 34.1931. 
* The writer wishes to express his thanks to Mr. H. R. Fulton and Mr. J. R. Winston, of the Office of 
Fruit-Disease Investigations, for the use of the laboratory facilities at Orlando, Fla., where most of the 
investigations recorded in this paper were carried on. During two months, January and June, 19x9, work 
on the problem was done at Cornell University, I th a c a , N. Y. Hie writer wishes to make special acknowl¬ 
edgment to Prof. H. H. Whetzel for the use of his own personal laboratory and greenhouse facilities, and 
for his invaluable suggestions and help throughout the course of the work. 
* Reference is made by number (italic) to “ literature dted,” p. 7x4-715. 
Journal of Agricultural Research, 
Washington, D. C 
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Mar. 3 , 193 3 
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