54 
THE COTTAGE GARDENER. 
May 
TvcJeeri, but which might, with more intelligence in 
its title, have been called Oidium vitis, or Egg-fungus 
of the vine. 
The generic name, Oidium, alludes to the egg-form 
of its spores or seed vessels; and is still further 
appropriate from their, and all the other parts of the 
fungus, having a pearly appearance, like that of the 
liglitly-boiled white of an egg. 
The mildew makes its first appearance on the 
underside of the vine’s leaves, probably because that 
side has least light and most moisture—circumstances 
favourable to the growth of all the fungi. By 
degrees it spreads, invades the upper surface of the 
leaves, and eventually covers the fruit also. To the 
naked eye it has a mealy appearance, like the mark 
left upon a dark cloth by contact with a floury hand, 
but when viewed through the microscope there 
appear pearly threads running, like minute sprigs of 
coral, over the surface of the leaf; and from the 
angles of these sprigs arise little oval bodies, which 
are the seed vessels. 
Of tliis fungus’s teuacity of life we have already 
given one instance, and we have witnessed another 
in the fact that after some of the vine’s leaves sent 
to us had been allowed to become dry and dead by 
exposure to the air in a warm room, yet the fungus 
upon them survived, and resumed its pearly appear¬ 
ance after being moistened with water for a few 
minutes. 
Knowing the powerfully destructive effect produced 
upon the fungus tribe by common salt, we instituted 
some experiments to ascertain its effect upon this 
Oidium. We all know that the common mushroom, 
sprinkled over with salt, dissolves away into a black 
liquid, which is the chief ingredient of catsup; 
'* and we also know that a solution of common salt 
sprinkled liberally over the stems of mildewed wheat 
destroys the fungus, Puccinia graminis, which is 
there established. Guided by these facts, we took a 
small piece of a vine-leaf thickly infested with the 
Oidium, and repeatedly agitated it in a solution of 
common salt—the solution being of the strength of 
sea-water, or four ounces of salt to the gallon. By 
degrees all the Oidium disappeared; and, after 
allowing the solution to remain on the leaf fragment 
for about two hours, scarcely a particle either of the 
pearly mycelium (the connecting sprig of the fungus) 
or of its seed vessels could be detected by the mi¬ 
croscope, though white lines and films, apparently 
their empty cuticles or skins, remained. 
Now, a gardener could not submit the leaves of 
his vines to such an agitation in salt water as that 
to which we subjected the fragment above named, 
but he could frequently and abundantly syringe 
them, or he could employ a woman to sponge with 
the saline solution every leaf shewing a symptom of 
the disease; and in either case, after allowing the 
solution to remain on the leaves for a few hours, he 
should syringe the whole plentifully with water only. 
Both the water aiid the solution should be of the 
same temperature as that of the vinery. To this 
treatment we would draw the consideration of our 
gardening friends, and recommend it to their earnest 
and assiduous attention. Fortunately, the only vine 
we have under glass has not a spot of mildew upon 
it, nor have any of the vines hi our neighbourhood, 
therefore we cannot cany our experiments further; 
but we can offer some few additional facts for the 
guidance of our readers. 
Very few plants are injured by a weak solution of 
salt remaining for a limited time upon their leaves ; 
and the following have been the results of our expe¬ 
riments with water containing four ounces per gallon 
in solution. Our experiments w r ere tried late in the 
afternoon of a cloudy and rainy day, such, we con¬ 
sidered, being most favourable for all operations 
requiring a plant’s leaves to be wetted. We dipped 
leaves, whilst still attached to the vine, into the 
above solution, and left as much of the solution 
upon them as wrnfld cling to them for one, three, 
and fifteen hours. At the end of those hours res¬ 
pectively, we washed the leaves in clear water, and 
not one of them suffered any injury. They are now 
growing as freely as any of the other leaves which 
have not been dipped into the saline solution. 
Sustained by these experiments, we recommend to 
all growers of vines attacked by the oidium to try 
the effect of a saline solution upon their mildewed 
vines. It will do no harm, at all events; and if they 
go by the following rules, we incline to the opinion 
that it will either very effectually check, or entirely 
remove, the disease. 
1. Use a solution not stronger than 4 ozs. to the 
gallon; and let the temperature of that solution 
be the same as the temperature of the vinery. 
2. Apply the solution about six in the afternoon ; 
let it remain on the leaves for twelve hours; 
then syringe it off with plain water, also of the 
temperature of the vinery. 
3. Repeat the application every evening, followed 
by as regular a syringing with water, until the 
disease is overcome, or the application is shewn 
to be of no avail. 
4. Sprinkle three or four pounds of salt over the 
surface of the border in which the roots of the 
vine are growing; for eveiy application aiding 
to impart salt to its sap is inimical to the fungus 
tribe. 
It will not be useless to inform our readers that 
this mildew is communicable by contact; for in 
many cases the plague may be kept within a narrow 
compass, if not entirely stayed, by picking off each 
leaf as soon as the leprous spot is perceived upon it. 
Nor is it communicable only from one vine leaf to 
another, but from the vine to other plants. Thus 
the Rev. M. J. Berkley relates that some healthy 
chrysanthemums, placed under a vine infested with 
the oidium, were all covered with the same fungus in 
