264 
as to the three points concerning which we have noted universal agree- 
ment it is no exception to the rule. I do not find in it the brown felt de- 
scribed by so many as characteristic of Ophiobolus, nor do I find con- 
stantly present any of the fungi mentioned above as the cause of foot- 
rot. Further long and patient investigation must determine which foot- 
rot, or which of its several types, is now interesting us in Illinois—if 
indeed it is any one of those yet studied. 
The name take-all is linked in the literature with Ophiobolus, and if 
the disease in Illinois is caused by Ophiobolus this name may be used 
properly in connection with it, but unless this is the case I prefer to 
employ the more comprehensive general name, foot-rot. 
Until definite knowledge is secured as to the cause of the disease it 
is impossible to predict its development, or to state whether it will recur 
in the same fields and spread to others. If it is identical with the Oregon 
disease which appeared in 1902 and apparently has attracted no attention 
since then (75), it may here lapse into a similar insignificant position. 
It should be borne in mind that the winter of 1918-19 was a very excep- 
tional one and of the type that is most favorable to foot-rot in Europe, 
and that in the absence of such winters the foot-rot may do little harm.* 
In our present state of ignorance as to the precise cause of this 
disease in Illinois it is impossible to give specific advice as to its preven- 
tion. A wise course, however, will be to avoid planting wheat for one 
year or, better, for two years, on lands where the disease occurred this 
year. Oats may probably be safely substituted. Burning over the 
stubble after harvest will also be a safe precaution. ~ 
ANNOTATED BIBLIOGRAPHY 
EXPLANATORY 
The asterisks used in connection with the entries indicate that the 
articles or books or pertinent passages cited have been carefully read in 
the original. My acquaintance with those not so marked has been gained 
through reviews or abstracts. The notes do not indicate the entire con- 
tent of the articles, but call attention to points most important in con- 
nection with the Illinois disease or in the general history of foot-rot. 
Information given in the preceding pages is not, as a rule, repeated in 
the notes. 
Quite a number of the entries lack the author’s name, since they 
either appeared anonymously or in secretarial or journal reports. Other 
entries are without title because they so appeared in foot-notes of articles 
read. It seemed ill-advised to omit them, though I was unable to verify 
the citations. For the sake of brevity the abbreviation E. S. R. is used 
to indicate the “Experiment Stgtion Record” published by the U. S. 
* Since the above was written, Dr. A. D. Cotton, of the Pathological Laboratory 
of the Kew Botanic Gardens, has examined the foot-rot in Illinois, and he tells 
me that the specimens he examined lacked the distinctive characters of take-all as 
that disease is understood in England. 
