32 MICROBES, FERMENTS, AND MOULDS. 
be acutely sloped, and the stalks of the plant should 
be turned down into the furrow, so that any spores 
which may be on the leaves may be washed off them 
by the rain, and not come into contact with the stem 
and roots of the plant. 
It is probable that earth-worms diffuse the spores 
of this fungus, as well of those of many other 
microbes. 
According to Prillieux, beetroot is attacked by 
another species of Peronospora, which causes the 
leaves of the plant to wither and fall. The remedy 
consists in burning the dead leaves on which the 
oospores remain during the winter, or, at any rate, 
in not allowing them to be placed on the dung-heap. 
The mildew which affects the vine is also a species 
of Peronospora (P. viticola) as we are about to show. 
V. Parasitic FuNGI oF THE VINE: O{DIUM, 
MILDEW, ETC. 
The parasites of the vine are so numerous as to 
require a separate chapter. Some years ago, in 1870, 
fifty of them were enumerated by Roumegutre, a well- 
known specialist, and the number is now more than 
doubled. We shall only now speak of the more 
important, of those which are especially injurious 
to the vine, and which consequently are the most 
interesting to us, 
