JOURNAL 
The New York Botanical Garden 
. VoL. X November, 1909. No. 119 
SOME PLANT DISEASES: THEIR CAUSE AND 
TREATMENT.* 
Plants like animals are subject to disease, and the knowledge 
of the cause and treatment of these diseases is one of the branches 
of botanical work which has grown, until today it is a science in 
itself. This is, to a large extent, due to the fact that the govern- 
ment, through its Agricultural Colleges, is appropriating annually 
large sums of money'to be expended in the investigations of the 
cause and treatment of the diseases of the cultivated plants; and 
well it may afford to do so, for to be able to combat successfully 
a single plant disease would bring in return to the country in a 
single year much more than all that is spent for this purpose dur- 
ing the same length of time. 
Almost every plant which grows has its characteristic disease 
and some plants are afflicted with many, so that the subject is a 
very extensive one and I can do nothing more this afternoon than 
to call your attention to a few of the most common plant dis- 
eases, give you some idea of their causes, and a few of the 
methods which have been employed for their treatment. 
Before taking up the subject of plant diseases proper, I want 
to mention briefly, by way of comparison, one of the chief causes 
of animal diseases. As you all doubtless know, many of the 
diseases of the animal body, speaking more particularly of the 
* An illustrated lecture delivered in the Museum building of the New York 
Botanical Garden, October 30, 1909 
241 
