568 
ago a number of small vineyards in Western Australia were rootep 
out or abandoned on account of this disease, which, at the time, 
was little understood. 
In 1850 the presence of the oidium was first reported in France. 
In four years this fungus, which settles upon the grape and ruins 
it without materially arresting the growth of the vine, reduced the 
production of wine by 80 per cent. Although sulphur was proved 
to check the disease, vinegrowers, alarmed at their losses, sought 
from America new varieties of vines said to be more resistant than 
the European kinds. Unfortunately, from the United States they 
also introduced on the oidium resistant vines the phylloxera pest, 
which was first noticed in the South of France in 1863; the 
ravages of this deadly vine root aphis gradually destroying almost 
the whole of the vineyards of France and of Europe, until by 
dogged determination and patient researches the new pest was 
in turn conquered. 
Although one of the most troublesome of the grape vine 
diseases, oidium is at the same time one of the easiest to sub- 
due, provided that the treatment be carried out with care. 
Like all powdery mildews, the parts attacked are covered over 
by the web-like threads of the mildew fungus. It only attacks 
those organs when green. It at first appears as a dirty white 
powdery film, possessing a characterisite mouldy smell. It leaves 
Oidium of the Vine. 
stains on the wood. Should it appear early, the flowers will fail to 
set ; then the more tender leaves will be covered with patches of 
microscopic threads, which will stop their growth and cause them to 
shrivel up and dry. The berries are most severely attacked. The 
effect of the parasite on the skin is to tighten it and cause it to 
loose its elasticity, so that the berries either dry up or burst open. 
