58 



the Oospores in the earth sticking to his boots. Mice may also spread 

 infection. 



Abies alba. J. Vindum Skov near Viborg (Gad). Pinus montana. J. Svine- 

 kl0v 0- P' Bang). Cattleya labiatae. S. Holte (A. P. Lier). Fagus silvatica com- 

 mon, f. inst. J. Sofienlund (Rosenkrantz) ; F. Hofmansgave (Aug. 78), Brsende- 

 skov; S. Kongsare (Kofoed), Farum Lillevang (Bonnevie), Sora Nordskov (R. 

 Leth), Thurebylund. Hellebonis niger. S. Valby (N. Jensen). 



36. Phytophtora infestans (Mont.) de By., Syll. VII =", Fisch. 

 IV''^^ Syn: Peronospora inf. (Mont.) Caspary, Kartoffelsvampen (R 82 

 b 3. P. N. 73 a 6. 76 c, la Cour 67), Kartoffelfarsoten (R 71 ''-^^l Kar- 

 toffelskimmel (R 93 c c. icon. & 02 a "«, Lind &. Ravn 10 «^ c. icon.), 

 Lit: 0rsted 63 c c. fig., Dybdahl 76 a, R 94 i. 



It is particularly found during the months of July to September; 

 its propagation depends very much on the weather, in some summers 

 (f. inst. 1911) it was hardly to be found; in other — more damp — 

 summers it caused great damage f. inst. 1844, 88, 91, 94, 1903 &. 07 (F. 

 K. R. 09). It was first found in this country, in 1841 (Fjeldstrup 44), 

 but it was not until the years 1844 &. 45 that it became conspicuous 

 in this country as well as in other Evropean countries (see R 84 d 6^ 

 J. L. Jensen 87 a). 



J. L. Jensen in particular deserves great credit for having studied 

 its propagation and control; he recommanded a special hilling of the 

 earth round the base of the plants to prevent the conidia from pene- 

 trating to the tubers. He wrote many treaties on this subject. These 

 made a great sensation on account of their being the first attempts on 

 a prevention of this scourge. Later on he also tried to desinfect the 

 tubers by means of hot water (40") which attempt was quite success- 

 ful, but this method is not of practical use. During the later years 

 other preventatives have been used (see F. K. R. 10 a). Rostrup has 

 requested the assistance of the legislators for prevention of the disease 

 (R 92 c). 



Solanum tuberosum common in gardens and fields. On forced potatoes in 

 hotsbeds it has been found as early as the end of March (J. Rosenvold Th. 

 Jergensen). Solanum laciniatum. S. Landbohejskolens Have; L. Fuglsang 

 (Thomsen). Solanum lycopersicum. F. Odense (Jak. Lge 88), Sore (Gram) and 

 many other places. Most frequently only the fruits are affected, the leaves, 

 however, may be so when the plant is not pruned, and the leaves have their 

 natural shape and size. Datura metel. S. Landboherjskolens Have (R 92 b ^3'' 

 a 92 g 65). 



37. Phytophtora syringae Kleb. (09 c. icon), Syn: Phloeophtora 

 syringae Kleb. (06 b.) 



Common on Syringa vulgaris var. cult, both in J. and S. causing great da- 

 mage in the nurseries (Lind 10 h). 



