120 Report of Schimmel $ Co. 1922. 



spreads round the branch the latter mortifies partly or totally. — The so-called Botrytis 

 rot of the rose buds occurs in the summer when in the flowering time the weather is 

 cool and damp. The rose buds, instead of opening, do not develop further, change 

 colour and get covered with an ash-grey coating of the fungus Botrytis cinerea, Pers. 

 (N. O. Mucedinacece.) Under favourable growing-conditions the plant is, in the most 

 cases, not liable to suffer seriously by this fungus. 



For combating these rose diseases the author recommends partly spraying with 

 sulphurated substances, e.g., powdered sulphur, solutions of calcium or potassium 

 sulphide, $c, in case of Sphaerotheca pannosa, partly prophylactic treatment with sprays 

 of copper preparations (copper-and-lime solution against Phragmidium, Actinonema, 

 Peronosposa and other leaf fungi). Careful treatment of the roses, such as proper 

 cutting and pruning, correct fertilization and tilling of the beds is likewise most essential. 



About 35 different fungi have been found on the various species of mint, but only 

 a part of them are parasites or cause diseases. Of the noxious fungi, the following 

 may be mentioned. Puccinia Mentha?, Pers. (N. 0. Pucciniacece), the very common mint 

 rust, occurs in two chief forms, the uredo- or summer-spores, and the teleuto- or 

 winter-spores. In summer time cinnamon-brown, wart-like, dusty pustules appear on 

 the back side of the leaves, at first sporadically, afterwards in growing numbers, which 

 constitute the stroma generating the unicellular summer (uredo) spores with pale yellow, 

 short-bristled membrane. The uredospores communicate the disease in summer from 

 leaf to leaf and from plant to plant. In addition to the brown pustules, largar black 

 dust-like tubercles appear, the teleuto-stroma of the same fungus. They generate the 

 oval, bicellular winter spores with a brown, wart-like membrane and long colourless 

 petioles. When these teleutospores germinate in the next spring and form sporidia 

 which infect the mint, the second, less common form of the disease develops in which 

 the stalks and the petioles of the leaves acquire abnormal stoutness and are streaked 

 by the mycelium of the rust fungus. The mint rust which occasionally causes deterioration 

 of the odour of the plant and its oil, and often enough has destroyed the entire crop, 

 is found not only on numerous species of Mentha, but also on various other members 

 of the family Labiatce (e. g., Calamintha, Clinopodium, Origanum, Satureia). However, 

 not all the species an infected equally often or in an equal degree. For instance, 

 Mentha arvensis is attacked by one of the eight different varieties of Puccinia Menthce 

 which does not or but slightly attack other species of Mentha. These biological properties 

 must be considered when combating the rust disease. By raising the mint plantations 

 in suitable uninfected soil the appearing of the disease can be warded off or at least 

 its spreading can be limited. 



Another disease, the so-called mint mildew, has been observed occasionally on 

 Mentha arvensis. The green parts of the plants get covered with a white, flour-like 

 coating which originates from an Erysibacea, Erysiphe Galeopsidis, D. C, or E. Cicho- 

 racearum, D. C. — The fungus Septoria Menthce, (Thurm) Oud. causes the septoria spotted- 

 leaf-disease of the mints which appears on the leaves of Mentha arvensis and perhaps 

 also of other species in shape of black-lined, dark, later on light-grey spots. The mint 

 septoria seems to be of minor importance. The same holds good for the following three 

 diseases: — The ramularia spotted-leaf-disease (caused by Pamularia menthicola, Sacc. 

 [Mucedinacece]) on the leaves of M. silvestris, M. aquatica, M. canadensis, M. arvensis; 

 the physoderma weal disease of mints (caused by Physoderma Menthce, Schroet. 

 [Cladochytriace.ee] and characterized by blackish-brown callosities on the stalks and 

 leaves of Mentha aquatica), and the synchytrium papillary disease of mints (caused by 

 Synchytrium aureum, Schroet. [Synchytriacece]), golden-yellow nodules on the stalks and 







