ON THE DISEASES OF PLANTS. 
41 
According to the experiments of Mr. Young on this subject, it appears that the 
best and simplest method for the prevention of these parasitical diseases in corn is 
to steep the seeds of affected plants in lime-water for twenty-four hours. When 
either the black or red parasite appears on other plants, treat them as for mildew. 
The leaves of several plants belonging to the kitchen-garden, viz. horse radish, 
cabbage, &c, are sometimes attacked by a parasitical plant ( Uredo Candida), in 
appearance not much unlike the ''mildew" to the naked eye ; this disease has been 
found from experience to be highly infectious. 
There is a curious parasitical disease (Mcidium grossularice) to which the leaves 
of gooseberry trees are liable. The only remedy for this, and the former disease, 
known is the removal of the affected leaves, and this can generally be done with 
safety, these diseases seldom involving many on the same plant at the same time. 
In this way they will be effectually prevented from spreading to the leaves and 
plants in the neighbourhood. 
Before we leave the subject of mildew and rust on plants, it may not be amiss 
to introduce a few figures of kinds very common, noticed by Mr. Rennie, Hort. 
Reg. vol. i. 468, and by Mr. Loudon, and figured Hort. Reg., vol. ii. page 328 * ; 
as first — 
The Cabbage Blight (Cylindrosporium con- 1 
centricum (1), wlrch has the appearance of small 
white patches, or specks of frosty incrustation, which 
when magnified are found to consist of a number of 
small cylinders, lying end to end or across each 
other. These are filled with seed and burst when 
ripe, scattering it in every direction. Wherever it 
falls upon the leaf it takes root, and the fungus spreads 
rapidly. 
Rose Blight. — All the Rosacea are subject to be infested with a fungus 
having the appearance of a brown powder, which makes its appearance first on the 
under side of the leaves ; this is the Uredo effasa, 2 
Greville (2). But besides this, there are two 
other species of fungi found only on rose leaves, 
the Puccinia rosce, Greville, and the Uredo 
rosce. 
Gardeners are well aware that if their dried 
specimens be placed in damp situations how soon 
they will become covered with a species of fungi, 
* Figures 1, 2, 3, were extracted from the Gardener's Magazine, vol. ix. page 325, and inserted in our 
Hort. Reg., vol. ii. page 328, but were omitted being acknowledged. 
VOL. II.— NO. II. G 
