50 VINES 
case the tissues of the fungus, or parasitic plant, 
appear on the outside of the leaf or fruit as 
a white, powdery, or downy substance. Since 
the nature of the disease is the same, its treat- 
ment will correspond with that for other fungous 
diseases, except that in greenhouses, flowers of 
sulphur can be used with considerable success 
and a great degree of simplicity. Sprinkle it 
on the plants in the morning, if the day promises 
to be clear, for if cloudy there will be no beneficial 
effect. That is, the fungicidal value of the sul- 
phur depends upon the fact that it is oxidized 
by the sun’s action, and the sulphurous acid that 
arises kills the fungus. 
Fortunately the fourth group of fungous dis- 
eases, that is, the rots, does not bother most 
vines. Its most severe form is illustrated in the 
case of the black rot of grapes. Either Bordeaux 
mixture or the copper carbonate solution should 
‘be used, although careful cultivation and the 
destruction of all prunings and litter about the 
vineyard will aid greatly in warding off this 
disease. 
Vines that should be watched for the appear- 
ance of fungous diseases are grapes, roses, some 
members of the clematis family, the cucurbits, 
and all other annual vines. 
