214 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in Austria. Experiment proved that the different varieties of cucumber 

 were not all equally liable to take infection, and that the fungus varied 

 in the size of the conidia according to the species on which it grew. 

 Bordeaux mixture has been used with good results as a fungicide. Kock 

 reports also on the American gooseberry mildew, which was introduced 

 with bushes from infected countries. Bordeaux mixture was effective 

 in checking the fungus. Leaf-rolling in potato-plants is due also to a 

 fungus, but weather conditions are powerful agents in inducing the ger- 

 mination and growth of the parasite. 



L. Hauman-Merck and J. A. Devoto* have published the first 

 attempt at a complete survey of plant diseases in Argentina. They 

 chronicle the occurrence of Phycomycetes, such as Cytospora, Plasmopara 

 (on the vine), and Peronosporse (on cabbage, lucerne, and spinach) ; one 

 Hyphomycete, Oidium (on vine) ; Erysiphaceas (on beans, oats, and roses) ; 

 Apiosporium (on cherry) ; Sclerotinia libertiana (on beans) ; Exoascus 

 deformans (on cherry), and Pseudopeziza medicaginis (on lucerne). 



A considerable number of rusts have also been identified on wheat, 

 oats, and maize, on fruit-trees, clover, shrubs, and trees, also smuts on 

 maize and other cereals and grasses. Several species of Sphasropsideae 

 have also been diagnosed belonging to the genera, Glozosporium, Cerco- 

 spora, and Septoria. Mycoidea parasitica was found on leaves of magnolia, 

 and Guscuta on lucerne. 



Diseases caused by insects are also included in the work. 



H. Klebahn t has studied a disease of celery that has been doing 

 much harm in the market gardens round Hamburg. The tubers and 

 base of the stem are affected, and the sheathing leaves on which the 

 fungus grows become scabbed and unsightly. If the celery is used in 

 the early season, not much damage is done, but in cases where it is 

 earthed up for later use, rottenness sets in and there is great loss. 



One of the fungi causing the mischief is Septoria Apii, but other 

 species of Sphaeropsideae are also to be found on celery, notably Phoma 

 apiicola, which is parasitic on roots, leaf-sheaths, and leaf-bases. The 

 fungus passes the winter in the soil, and attacks the young plants in 

 spring. 



The diseases of cultivated plants have been treated in two divisions 

 for the Encyclopedic Agricole. The first, by G. Delacroix f describes 

 the various pathological conditions of the plant organisms as repre- 

 sented by teratological formations induced by wounding, frost, soil, 

 conditions, etc. 



The same author,§ along with A. Maublanc, has written on para- 

 sitic diseases induced by phanerogams, fungi, bacteria, and epiphytes. 

 Causes that lead to attack, and methods of treatment, are dwelt on, 

 and the whole made useful to the cultivator. 



Some diseases of cultivated plants from the tropics have been 

 recorded by Brick, || especially those that attack economic plants such 



* Bol. Minist. Agric. Buenos Aires, x. (1908) pp. 98-113. See also Bot. Cen- 

 tralbl., xxv. (1909) p. 520. 



t Zeitschr. Pflanzenkr., xx. (1910) pp. 1-40 (2 pis. and 14 figs.). 



J Paris : J. B. Balliere (1908) xii. and 431 pp. (58 pis.). 



§ Paris (1909) 452 pp. (83 pis.). See also Centralbl. Bakt.,xxv. (1909) pp. 518-19. 



|| Jahresb. Ver. Angew. Bot., 1908 (Berlin 1909). See also Centralbl. Bakt., 

 xxv. (1909) pp. 522-3. 



