THE FUNGOIP DISEASES OF PLANTS. 295 
plenty of moisture within so that it is no longer dependent upon the 
weather. 
The effects produced by these fungi growing in the plant tissues 
are extremely varied. Any part of the plant may be affected, some 
diseases showing in one place and others elsewhere. The leaf may 
become covered with spots of various colors, or it may wilt, or 
rott up or drop off. Scabs may grow on the plant or its fruit, or the 
whole may show signs of rotting. Plant diseases have received 
various popular names that are loosely applied and not very clear 
in their meaning. The more common descriptive names are the 
following: 
Wilts are characterized by the wilting and withering of the plant. 
Rots are characterized by a tendency of the plant tissue to 
soften and decay. 
Smuts show a mass of black or blackish spores. 
Mildews show a whitish, powdery growth over the surface of the 
host. 
Rusts show spots of a reddish color, due to reddish-yellow 
spores. 
Anthracnose is a name frequently applied to diseases causing 
spots on the leaves or elsewhere. 
Blight is a term with no definite meaning, but is generally ap- 
plied to almost anything that causes a general wilting and destruc- 
tion of the plant. 
These terms are all in a measure descriptive terms of the effects 
produced by the parasites on the host. None of them are specific 
diseases, but all are produced by many different parasites on many 
different hosts, and in some cases the same parasite may produce 
different types of disease at different stages of its life. 
Methods of Combating Fungoid Diseases. There are 
several general methods by which these diseases may be kept in 
check: i. By the selection of resistant varieties of the cultivated 
plants. Experience has shown that some varieties yield readily to 
the parasites while others are highly resistant. A careful selection 
of the varieties, guided by experience, is sometimes of value in 
checking disease. 2. By regulating the conditions of the cultivated 
