ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 34l> 



an alga which kills the twigs or forms a lichen which is equally fatal to 

 the leaves. A large number of fungi are recorded on grasses and cereals. 

 Potatoes, tomatoes, sugar-cane, and palms have all suffered from various 

 parasitic fungi. Calms Deodora was destroyed by Polyporas annosus. 

 Acacia arabica was killed by Fames Passianus, not hitherto considered 

 a parasite. Trichosporium, Pcridermium and Uredo have also attacked 

 various trees. 



Plant Diseases during the Year 1903." — M. Hollrung has just 

 issued the " Jahresbericht," dealing with diseases of plants caused by 

 animals, plants, or unfavourable conditions. He treats the latter first, 

 as general injury due to temperature, light and shade, poisons, 

 wounds, crowding, etc. The larger part of the volume is occupied by 

 an account of special cases of disease, first of the agents causing disease, 

 and secondly of the different plants that have been recorded as attacked 

 during the year. 



A chapter is devoted to plant hygiene, and the conditions that are 

 most favourable to the healthy development of plants in enabling them 

 to withstand the attacks of fungi, insects, etc. The author finally deals 

 with various remedies, the encouragement of certain fungi that prey on 

 insects, or of birds that devour insects, which are included under 

 "organic" remedies. The inorganic remedies are the chemical com- 

 pounds, applied as sprays, etc., which have been found to destroy the 

 pests without injuring the host-plant. The editor gives, in this work, the 

 results of 2207 original papers, the bibliography of which is published 

 after each section to which they relate. 



Diseases of Cultivated Plants.j — M. C. Cooke has collated the 

 different fungus pests of the ornamental shrubbery. He describes a 

 large number, mostly leaf diseases, so that they may be recognised by the 

 gardener. In many cases he advises as to the remedies to be used. In 

 another contribution % he describes the disease called Apple and Pear 

 Scab, due to the fungus Fusidadium pirininm and F. dendriticuni. 

 These diseases have been very destructive in Tasmania. 



E. S. Salmon § gives an account of the American Gooseberry Mildew, 

 of which the first recorded appearance was in Ireland in 1900. It has. 

 spread to a number of localities ; since that date it has been found in 

 various parts of Russia, and more recently in Denmark. Besides the use 

 of fungicides, Salmon recommends burning the affected parts. 



Geo. Massie || writes on some diseases of the Potato. He describes the 

 havoc wrought by Phytophthora, Nectria, JEdomyces and Sorosporium. 

 He also describes a disease due to Bacteria, which has been very destructive 

 in America, and which has occurred once or twice in this country. 



Plant Diseases. — G. LustnerlT has examined a large number of leaves 

 of the vine affected by the " red brand." He has failed to find the 

 fungus Pseudopeziza, and thinks the disease must be due to some other 



* Jahresber. Pflanzenkr., vi. (1903), Paul Parey (Berlin, 1005) viii. and 374 pp. 

 t Journ. Roy. Hort. Soc, xxix. (1004) pp. 1-25 (3 col. pis.). 

 X Tom. cit., pp. 91-2. § Tom. cit. pp. 102-10. 



H Tom. cit., pp. 139-45 (6 figs.). 



\ Ber. K. Lehr. fiir Wein. Obst. Garten, zu Geisen. a Rh. fur das Etatsjidir 19"3, 

 pp. 190-1. See also Centralbl. Bakt. xiv. (1905) pp. 147-8. 



