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. viticold) as we are about to show. 



V. PARASITIC FUNGI OF THE VINE: OIDIUM, 

 MILDEW, ETC. 



The parasites of the vine are so numerous as to 

 require a separate chapter. Some years ago, in 1870, 

 fiftv of them were enumerated b}^ Roumeguere, 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. 



