226 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The pale-red mycelium of the fungus had penetrated the tissue of the- 

 root and caused the death of the vine. The fungus fructification* 

 appeared in the vineyard in May and August. 



The same writer* has studied the best methods of destroying 

 Botrytis and MoniUa. A solution of calcium bisulphide was found to* 

 be most effectual. He tested the influence of cold and heat on the 

 spores, and other conditions that would influence their vitality. 



Vegetable Pathology.f — Under this heading P. Yiala and P. 

 Pacoltet give the results of their culture of the fungus, Guignardia- 

 Bidicellei, which causes black rot of the vine. After isolating the- 

 fungus they tested its growth on various media. They found as a result 

 of these experiments- that its vitality depended on the amount of acid 

 and of sugar in the culture, and also in the host plant at the time of 

 attack. It flourishes most luxuriantly after a fall of temperature, and 

 at the stage before the fruit ripens. This also explains why some fruits 

 are more susceptible than others to the attack of this fungus. 



The Action of Fungi on Woody Cells.! — It has been stated by- 

 various workers that the action of parasitic fungi on trees is to delignify 

 the vessels and fibres of the wood. M. C. Potter found that boiling, or 

 prolonged immersion in water, had the effect of destroying the lignin 

 and leaving a layer of cellulose. He found the cellulose layer present 

 in the wood vessels of a number of living trees that were unattacked by 

 any fungus. He comes to the conclusion that the extraction of the- 

 lignin and consequent exposure of the cellulose is due in many 

 instances to the method employed for sterilizing the wood used in 

 experiments, and that where the cellulose layer is present in the living 

 tree, it probably represents a stage of arrested development. 



Annual Record of Plant Diseases.§— In the yearly volume for 1902,. 

 which has just been issued, M. Hollrung, the editor, has introduced 

 several new features. He gives more attention to the manifestation of 

 disease, and he has associated with him a number of coadjutors in hi& 

 work. In the different sections he gives abstracts of the more im- 

 portant papers bearing on the subject under discussion, and also a 

 bibliography of all recent papers connected with it. The subjects 

 treated in order are general Phytopathology and Pathological Anatomy ;. 

 the cause of disease, whether the parasite be plant or animal, discussedi 

 generally, and then with reference to definite hosts ; plant hygiene,, 

 including considerations of climate, soil, immunity, etc. ; and, finally, 

 the various methods of combating disease, organic and inorganic. 

 Organic methods may be illustrated by the attempt to infect locusts 

 with the fungus Empusa Grylli, which is fatal to the grasshopper tribe. 

 Inorganic includes all the chemical and mechanical appliances that have- 

 been found useful in this warfare. A copious subject index adds to the 

 value of the book. 



* Zeitschr. Magyar, bot. Lapok., ii. (1903) pp. 132-3. See also Ann. Mycol., L 

 (1903) p. 559. 



t Comptes Eendns, cxxxviii. (1904) pp 306-S. 



I Annalsof Botany, xviii. (1901) pp. 121-40 (1 pi.). 



§ Jahrcsb. Pflauzenkrank., v., Berlin, 1904, viii. and 408 pp. 



