e is seldom
troublesome on plants grown thinly in the open air. If it makes its
appearance, water thoroughly, but not too often, and sprinkle dry sand
over the seed-bed among the plants.[D]

BLACK LEG OR MILDEW.--This is a disease which attacks the stems
of young plants which are being wintered over. It is undoubtedly due to
one or more species of parasitic fungi, but I do not find that the
subject has been studied. Doubtless the rupture of the bark by alternate
freezing and thawing gives the fungi an opportunity to attack the plant.
The disease is prevented and kept in check by keeping the seed-bed dry.
An occasional dressing of sand, lime, wood-ashes or rubbish of any kind,
is useful.

FOOTNOTES:

[B] _Bull. Soc. Bot. France, 1886_ (_Rev. Bib._, p. 128). La cancrena
del Cavolo Fiore (_La gangrene humide du Chou-fleur_) par M. le
Professor O. Comes (_Atti del R. Instituto del incorraggiamento alle
Scienzie naturali._--Estratta dal Vol. IV, 3a serie, degli Atti
Academici, 1885). [The Humid Gangrene of the Cauliflower.]

"A disease which attacks the crops of cauliflower around Resina and at
Torre del Greco, near Naples. The roots of the diseased plants remain
sound, or at least appear so, but the subterranean parts of the stem are
more or less seriously affected; the bark is disorganized, the wood
situated beneath it more or less decomposed, and the pith destroyed for
a variable length. Upon microscopic examination the vessels are found
filled with gum. M. Comes recognizes in this disease all the symptoms of
the affection which has been designated under the name humid gangrene.
He thinks that it is the same disease which, by German authors, is
attributed to the parasitism of _Pleospora Napi_, Fuckel, or to its
conidiferous form, _sporidesmium excitosum_, Kuehn. But he considers the
presence of these parasites as an accessory phenomenon, as well as that
of _Cladosporium_ and _Macrosporium Brassicae_. In his opinion the true
cause of the alteration of the cauliflower is the humid gangrene, that
is to say, a gummy degeneration and putrid fermentation of the tissues,
caused by the abundance of manure in the soil and the excess of water in
the plant at a time when it is subject to sudden changes of temperature.

"This disease is not confined to cauliflowers; it is common in all
garden vegetables, and is of the same nature as that which attacks
tomatoes and which was described by this author in the same journal in
1884."