62 EXPERIMENT STATION RECORD. 



carried on by the consulting botanist for the year ending 1903. During this time 

 154 samples of seed were examined for their purity and germination and a consider- 

 able number of diseases of plants, weeds, and poisonous plants reported upon. 



Among the plant diseases reported a description is given of a disease of turnips 

 which has proven rather serious in parts of England. This disease was of fungus 

 origin and it is believed to be due to Phoma napo-brassicse, which was first described 

 in 1893 (E. S. R-, <>, p. 737). For the prevention of this disease the author suggests 

 the removal and destruction of all affected roots, and on the assumption that the 

 fungus leaches the root through the leaves the foliage should be sprayed with either 

 a solution < f copper sulphate or, what is probably better, a rather strong Bordeaux 

 mixture. Miscellaneous notes are given on a number of other diseases. 



Diseases of plants cultivated in Connecticut, <i. P. Clixtox {Connecticut State 

 Sta. Iipt. 1903, pt. 4, pp. '£79-370, pis. 21).— The author describes the causes of plant 

 diseases and discusses parasitic fungi of different kinds. Notes on the prevention of 

 diseases, directions for the preparation of fungicides, and descriptions of various 

 kinds of spraying apparatus are given. Following these, notes are given on some of 

 the more specific diseases that have been noticed within the past 2 seasons, the 

 arrangement being by an alphabetical list of the hosts. 



Plant diseases in 1901-2, Weiss ( Vrtljxchr. Bayer. Landw. Bat., 8 {1903), No. 4, 

 pp. 640-668; Sup., pp. 733-763). — The occurrence of various plant diseases and inju- 

 ries due to parasitic organisms, physiological disturbances, and insect attacks are 

 noted, and suggestions are offered for the protection of plants from injury. The 

 notes are arranged according to the host plants. 



Plant diseases in Denmark, 1902, F. Rostrup (TMsskr. Landbr. Planteavl, 10 

 (1904), pp. 361-379). — A review is given of the more important diseases of plants 

 observed during the period. 



Letters on the diseases of plants, N. A. Cobb {Agr. Gaz. New South Wales, 15 

 (1904) , No. 1, pp. 1-19, pis. 6, figs. 10). — Notes are given on a number of diseases of 

 plants, among them the brown rot of fruits due to Monilia fructigena, a cherry blight 

 due to a Dematium-like fungus, various rusts and smuts of cereals, some diseases of 

 citrus fruits, black spot of apple and pear, etc. 



Some unusual fungus diseases in Iowa during the summer of 1903, L. H. 

 Pammel (Proc. Soc. Prom. Agr. Sci., 1904, pp- 144-156, pis. 2). — Notes are given on a 

 number of fungus diseases of economic plants which are either of quite recent occur- 

 rence within the State or which possess some unusual features. 



A discussion is given of the relation between climatic conditions and fungus devel- 

 opment in which it is shown that many fungus diseases are favored by a combination 

 of climatic conditions while others do not seem to be affected. The downy mildew 

 of the grape is said to be favored by moist, damp weather, while the powdery mil- 

 dew is favored by drier weather with frequent dews. The mean temperature and 

 precipitation at the Iowa Station are given for a number of years, and accompanying 

 them are brief statements regarding the occurrence of a number of diseases. 



Chlorosis of plants: Cause and prevention, A. Demextyev (Zliur. Opuitn. 

 Agron. [Jour. E.xpt. Landw.], 4 (1903), No. 6, pp. 714-733).— The author critically 

 examined the various hypotheses regarding the cause of chlorosis, and from his ob- 

 servations concludes that in the majority of cases chlorosis is caused by parasites 

 upon the roots of the plants. Beginning usually with the more minute divisions of 

 the roots the parasites lay bare the ends cf the vessels, interfering with the normal 

 course of the absorption of the soil solutions. 



The author believes that chlorosis develops as follows: Owing to the evaporation 

 of water through the leaves and to the negative pressure thereby produced in the 

 stem of tree-like plants, the salt solutions enter directly from the soil into the vessels 

 of the roots which have been laid open by the parasites. These rise into the leaves 

 where, through evaporation, they attain a high concentration. Under the influence 



