Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 130 PHYCOMYCETES. wet season is very favourable to it. The mycelium is uon- septate and spreads through the intercellular spaces of the host, nourished by button-like haustoria sunk into the host-cells. The antheridium comes into contact with the oogonium by a fertilization tube, which, however, remains closed. The oospores hibernate in leaves and fruit. Frcvcntion} Ammoniacal copper carbonate solutio
Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 130 PHYCOMYCETES. wet season is very favourable to it. The mycelium is uon- septate and spreads through the intercellular spaces of the host, nourished by button-like haustoria sunk into the host-cells. The antheridium comes into contact with the oogonium by a fertilization tube, which, however, remains closed. The oospores hibernate in leaves and fruit. Frcvcntion} Ammoniacal copper carbonate solution, eau celeste, or Bordeaux mixture, prepared as described on p. 69, may be used. The tirst-named solution seems least liable to injure the foliage; the others must, on this account, be used with care. The first application is made about the time the Fig. 41.—Plasmopara pycimaea on Anemone nemorosa. Conidiophores emerging from a stoma. Intercellular mycelium with haustoria. (v. Tubeuf del.) berries are well formed, and the sprayings are repeated every twelve to fifteen days, or ofteuer if there are heavy rains, till the grapes begin to colour. It must, however, be remembered that sprayings of this kind do not reach the mycelium inside the leaf, but only act superficially, killing any developing conidiophores or conidia which may alight on the leaf. These fungicides are, at the same time, remedies for powdery mildew (Uncinula). ' Sulphuring' as a remedy for this and the powdery mildew- has been recommended hy continental writers. The burning of all diseased vine-leaves is strongly recommended. Attention also should be given to the cultivation of disease-proof varieties. PI. pygmaea (Unger). On Ranunculaceae (Britain and America). PI. pusilla (De Bary). On Geraniums. 1 Galloway, 'Fungous diseases of the grape and their treatment,' Dept. of Aijric, Farmera' Bulletin, No. 4, 1881. -Oesterr. Weinbaukongress, 1891. Reported in Oe-it. landwirth. Wochenhlatl, X., 1881. M
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