6 
N. C. Experiment Station 
fungus which is designated, Sclerotinia trifoliorum Erik. In 1890 
(19) the disease was reported as more destructive to Medicago lupulina 
in Denmark than to species of Trifolium. Subsequent accounts by 
European investigators deal primarily with experimental procedures 
looking toward the control of the disease. 
Steir rot has not only been prevalent in continental Europe, for a 
long time, but it very probably was the cause of lands becoming “sick of 
red clover,” hence the name clover-sickness in the British Isles, as 
early as the early part of the nineteenth century. Investigations on 
clover sickness were begun at the Rothamsted Experiment Station, 
England, in 1849 (12) but the relation of the disease to the fungus 
Sclerotinia trifoliorum was not established until 1897 (3). English 
writers had previously expressed a variety of views in regard to the 
cause of clover sickness. Carruthers (3) at this time ascribed the dis¬ 
ease to the fungus in question and suggested methods for its control. 
The first observation of the occurrence of clover stem rot within the 
United States appears to have been made in 1890 in Delaware (2). 
While the disease was during subsequent years noted in several other 
States, it appears not to have been sufficiently destructive to incite inves¬ 
tigation. In 1914-1915, however, it was reported by Gilbert and Myer 
(10) to be productive of serious damage to young alfalfa plants in 
Kentucky. This report and a subsequent one (11) constitute the only 
American accounts which indicate any considerable study of the disease. 
Distribution of the Disease 
As indicated above, the disease is known to occur abroad in Germany, 
Denmark, Sweden, and England, and in America within Delaware and 
Kentucky. It has furthermore been recorded from Canada, New York, 
New Jersey, Virginia, Indiana, Oregon, and North and South Carolina. 
Its prevalence in these states indicates that it very probably occurs in 
other of the states where clover is grown. Its distribution within North 
Carolina is not completely known, but since clover is generally grown 
throughout the State and since the points from which collections of dis¬ 
eased material have been made are quite widely separated, it is believed 
that the disease is generally prevalent. As indicated bv these collections 
the disease is known to occur within thirteen counties, namely: Ala¬ 
mance, Chatham, Columbus, Edgecombe, Eorsyth, Granville, Halifax, 
Lincoln, Mecklenburg, Moore, Orange, Rowan, and Wake. 
Host Plants 
The disease has been shown by European writers to attack red clover, 
white clover, crimson clover, alsike clover, sainfoin and alfalfa. To this 
list Gilbert and Myer (10) have added spotted spurge, Euphorbia macu- 
