PARASITIC FUNGI AND MOULDS. 37 
hybernate in the tissue of the leaf itself (Fig. 17, b), 
and germinate in the spring. The conjugation of the 
sexual spores, as well as the ripening of the summer 
spores, and the germination 
of the zoospores which issue 
from them, can only occur in 
a drop of water, rain, dew, 
or mist, so that a persistent 
drought checks the propagation 
of this fungus. 
The parasite injures the 
stock by stripping it of its 
leaves, thus hindering the nu- 
trition of the plant; moreover, 
the grapes, since they are im- 
perfectly protected from the 
sun, dry up before they are Fig. Fiietartis of tufts of Pero- 
ripe. Sometimes, also, the  — Bgore inekans isauing vom 
fungus attacks the grape itself, spore(x dee 
or its peduncle, 
Vines planted in a moist soil resist its attacks 
better than others, simply because the nature of the 
soil makes the plant more vigorous, and suitable 
manure acts in the same way. When the fungus is 
developed, it may be destroyed by sulphur mixed 
“ with powdered lime. Since its mycelium is more 
deeply seated than that of oidium, it is necessary 
to have recourse to more vigorous measures in order 
to reach it. Powdered borax has also been pre- 
