June, 1921] 
STEVENS PLANT PATHOLOGY 
rice smut, properly named Tilletia horrida by the Japanese, which was 
eradicated from South Carohna in 1898 by Dr. A. P. Anderson. 
Citrus canker was more tardily recognized, but the expenditure of 
$1,500,000 by Florida to protect a crop worth $50,000,000 annually and 
promising to be worth twice that is freely made. The number of cankered 
trees found in Florida in 1915 was 6,715. In 1919 it was reduced to 4. 
Perhaps the most significant of cases is that of flag smut of wheat. Picture 
this as spread over the wheat areas of the United States with an annual loss 
of nine million bushels to occur over a long period of years. Let us hope 
that the gravity of the situation is realized and that the appropriation and 
activities suffice not only to hold it within its present limited range of one 
county, but actually to eliminate it. 
The decay of structural timber, while not, strictly speaking, due to 
disease, falls within the province of pathology. I can merely hint at the 
benefits that occur through activities in this field. Certain plant diseases, 
as the ergots of grain and grasses, have caused serious inroads upon 
human health and that of cattle. These the science of plant pathology 
alleviates. I trust that I have given you a partial picture, a mere glimpse 
here and there, to indicate the manifold, broad, important relations existing 
between the science of phytopathology and human welfare. Such in general 
are the field and the achievements, the relations of the science. All the facts 
that I have presented were doubtless known to many of you ; perhaps some 
were not known to all. 
The utility of the science is broadly attested and indeed is unquestioned. 
Benefits almost inconceivable will result from such extension, or other 
propaganda, as bring into actual use the knowledge that science has already 
given us. With the further accumulation of knowledge by the present 
types of research, other vast benefits will arise regarding each one of the 
numerous diseases. None is so well studied that further searching will not 
be rewarded, as is attested by many recent investigations. Accurate 
knowledge of the flight of sporidia of Gymnosporangium or of ascospores 
of Venturia, for example, may lead to important modifications of practice. 
Bud hibernation of the mycelium of a previously much studied group of 
fungi was but recently discovered. 
It is to be observed that the great discovery of the parasitism of the 
fungi and the founding of bacteriology and the development of its metho- 
dology, together with the early foundations laid through the years in his- 
tology, mycology, taxonomy, and physiology, have furnished the bases on 
which plant pathology has made its advance. Aside from these there 
have been few, if any, great fundamental contributions. 
In the earlier days, descriptions, recognition of causes, and trials of 
obvious prophylactic measures was the usual order. Officials and the 
public desired immediate recommendations. This type of work as regards 
the really important diseases has largely been done, and now is the period 
