No satisfactory remedy is known for the disease. The avoidance of damp soils and locations would be of some benefit, but is hardly practicable with the cauliflower. Wide planting is practiced on Long Island in order to diminish the tendency to the disease. It undoubtedly has this effect to some extent, by permitting a more free circulation of the air, thus drying up the moisture on the plants and thereby lessening the opportunity for the germination of the spores. The increased distance may also diminish the chance of the spread of the spores from plant to plant. When this disease appears upon the early crop in hot-beds or cold frames it may be kept somewhat in check by giving as much air as possible, and taking care not to apply water to the leaves.
Damping Off.—This is usually due to a species of Pythium (a fungus closely related to that which causes the potato rot), which attacks the young plants soon after they germinate. The remedy is, to give the plants plenty of air until their stems become strong enough to resist its attacks. An additional precaution sometimes employed is to grow the plants in pans or small boxes and water them only by setting these in a tank of water of nearly the same depth, allowing the water to soak into the soil, but not touch the plants. The disease 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, 3^a 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 Brassicæ. 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." [This disease is also mentioned by Victor Paquet, in his "Plantes Potagers" (London, 1846, p. 243), where it is attributed to stagnant moisture].
[C] Country Gentleman, 1889, p. 769, (from the Port Jefferson Times, Sept. 27):
"Close upon the heels of a partial failure of the potato crop through rotting comes the news from various points on Eastern Long Island that the cauliflower crop has almost totally failed through the same cause. In Manorville the crop has not sufficiently developed in some of the fields to warrant picking, and in Mattituck and east of that place the rotting will result in an almost total loss. In a few cases there is not yet any indication of rot, but the farmers are afraid to tie the plants up lest rotting ensue.
"In East Moriches, Orient, and the near vicinity, the yield will not be of sufficient value to pay for plowing the ground, not to speak of the other expenses which have been entailed. Through the Hamptons careful observations failed to reveal scarcely a single successful crop.