Dr. Good, the distinguished medical writer, has remarked, that the morbid affections to which the vegetable part of the creation is liable, are almost as numerous as those which render decrepid and destroy the animal tribes. It would be difficult, perhaps, whatever system of nosology is followed, to place a finger upon a class of animal physical diseases of which a parallel example could not be pointed out among plants. The smut which ravages our corn crops; the mildew which destroys our peas; the curl that is annually infecting more destructively our potatoes; the ambury, or club-root, to which our turnips and other species of brassica are liable; the shanking, or ulceration, which attacks the stalks of our grapes, are only a few of the most commonly observed diseases to which the plants we cultivate are liable.

Disease is the negation of health; and as the health of a plant is the correct performance of its functions, disease may be defined to be an incorrect performance of the functions. Such incorrectness arises from four causes - vital energy declining from old age - parasites - improper food, either in quality or quantity - and inauspicious temperature. If these could be all avoided, a plant might enjoy a vigorous immortality. Such, however, is not the lot of any organized being, and in proportion to the debilitating circumstances are the nature, the intensity, and final consequences of the disease induced. The little known relative to the diseases which infest the gardeners' crops, will be found under their respective titles.

Diseases #1

Shanking is a moist gangrene, attacking and destroying the stalk of the grapes, arising apparently from the temperature of the soil being unsuitably below that in which the branches are vegetating.

Warts On Leaves

Dr. Lindley says, "The appearance of warts on their under side, is most probably caused by damp atmosphere and rich soil, and may be conceived to arise thus: the water which the leaves derive from the stem, and absorb from the atmosphere, is unable to escape again, in consequence of the air that surrounds them being continually loaded with moisture; the result of this is, that the water accumulates in the interior of the leaves, and swells them up in the form of warts. The presence of the latter on the under side only, is owing to perspiration from the vines, taking place principally by that surface, which is, moreover, much softer and looser in texture than the upper surface." - Gard. Chron.

Rust

The rust of the vine is a disease which attacks the grapes, covering them with a tough brown skin, which is incapable of natural extension, and which stops their growth. Wherever the disease appears, the crop is injured or even ruined. Various causes have been suggested as the origin of this disease; but the true origin I believe to be a sudden unhealthy reduction of temperature whilst the grapes are young. From one frosty night I have seen the fruit of apple trees infected with a very similar induration of the skin.

Bleeding

If pruned late in the spring the vine is very liable to bleed at this season. A red hot iron applied to the wound until it is partially charred will stop the effusion of sap for a time, and to render the cure permanent, the place should be well rubbed and coated with a paste made of newly burnt lime and grease. This hardens and forms an effectual plaster.

Shrivelling arises in the berries from a want of sap. It is caused by several modes of bad cultivation, as excess of wet and cold to the roots; over-heating and subsequent reduction of temperature in the house: and by thinning the leaves erroneously.

Insects Infesting The Vine

See Scale, Thrips, Wasp, etc.