File:The American garden (1873) (17528281653).jpg

Title: The American garden
Identifier: americangarden111890broo (find matches)
Year: 1873 (1870s)
Authors:
Subjects: Horticulture; Gardening
Publisher: Brooklyn, N. Y. : (s. n. )
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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DA MPIN G - OFF. 349 falls over. In many cases, the top of the plant may re- main alive and fresh for some days after it has fallen over. It is commonly supposed that damping-oft is due to a
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Fig. 6 Fig. 3. fungus. The fungus which has been called the "pot- ting-bed fungus" in Europe is commonly supposed to cause the difficulty, but the subject is little understood in this country. It is by no means certain that all damping-off is the same. It is possible that two or three distinct troubles are called by the same name. Damping-oft is most troublesome under glass and among plants which are crowded, but it may occur in the nursery-row out of doors. Certain conditions of atmosphere and culture induce the attack of the fungus. In my experience and observation, a soil dry beneath and wet on top afiords the best conditions for damping- off. It is a common fault to merely sprinkle the propa- gating bed, allowing the under soil to remain dry and powdery. The operator may suppose that he has given enough water to wet the soil throughout. This condi- tions of affairs is particularly apt to occur when water is applied from a hose, for I find that there is then a ten- dency to apply too little rather than too much. The amount of water can be guaged more readily if applied from a pot. There is little to be done in the way of a remedy for damping-off', for unless the plants are particularly valua- ble it will scarcely pay to attempt to save them after they are attacked. But preventives can be employed. Keep the plants stocky, never allow them to crowd, give plenty of air, and endeavor to keep the soil uni- formly moist throughout. From Professor A. B. Seymour, lldi vard Univer- sity.—In his " Enumeration of the Peronosporea: of the United States," Professor Farlow says: "In this coun- try the species of pythium have not been sufficiently studied, and no mention is made of them in this Daper, although they possess a decided agricultural interest, since one species apparently causes what is known in some parts of the eastern states as the potting-bed fun- gus, which is very destructive to young house plants in the winter. Other species are known in decaying plants in damp ground." This is the extent of our knowledge of the subject in this country. In Europe there are several species of interest in this connection.* In 1878 DeBary observed plants of CIl'oiuc ^'iolaira which turned brown near the surface of the ground and also in spots on the stem and leaves. The plants wilted and became foul or dried up. The next year they were worse and several additional species of flowering plants were attacked. All the discolored tissues were found to contain mycelium, sometimes of several kinds, but only one kind was present in every case and that was Phytopli- llioi-a oiiinivora (or Pvlliiuin oiiuii't'ora), a species closely allied to the potato rot fungus. Conidia-bearing branches of the mycelium (Fig. i) grow out through the epidermis and the conidia germinate by forming zo- ospores (Fig. 2). The resting spores (Fig. 3; correspond to those of the grape mildew. I do not understand that this fungus lives in the soil. Pythium is a fungus allied to phytophthora, but appar- ently lower in rank, Pytliiiini 7u:\ii/is was found by De- Bary growing on potato tubers which had already been partly rotted by the common potato rot fungus, Phytofh- thora infestaiis. He found that the pythium would *Bop. Gaz., 1883.

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