DISEASES OF PLANTS. 449 



When several diseased areas are present tbe canes are killed outright during 

 the winter, whereas when only one or two infected areas are present the canes 

 may survive and produce a certain amount of fruit. Infection mostly talies 

 place during the fruiting period, hence spraying can not be successfully re- 

 sorted to unless the fruit is sacrificed. If spraying is found desirable the use 

 of Bordeaux mixture is recommended. All diseased canes should be cut out 

 and burned as soon as noticed, and the practice of allowing dead canes to re- 

 main standing throughout the winter is condemned. 



The second fungus forms white patches on the stems, studded with black 

 dot-like fruits. For the control of this parasite, treatment similar to that 

 suggested for //. rubi is recommended. 



Invasions of downy mildew in southwest France in 1911, J. Capus {Rev. 

 Vit., 37 {1912), No. 958, pp. 568-571).— A detailed account is given of the 

 author's observations made on the 7 outbreaks and the progress of grape mildew 

 in the vineyards of Gironde from June to September, 1911. 



Conditions for development of downy mildew. — Temperature, L. Ravaz and 

 G. Verge {Prog. Agr. et Vit. {Ed. VEst-Ccntre), 33 {1912), No. 16, pp. .'/.SJ- 

 48S). — The authors reiwrt on a continuation of their studies (E. S. R., 27. p. 

 49). 



Both young and mature leaves of grapes were inoculated at from 7 to 14° C. 

 with spores in a very moist atmosphere, the controls ranging from 18 to 35°. 

 It was found that the inoculations at temperatures down to 8° showed conidio- 

 phores in from 4 to 5 days, but those at 7° failed to develop the infection. 



ExT»eriments to determine the danger period from possible infection were 

 also carried out under varied conditions. Conidia on glass plates in a very 

 moist atmosphere under bell jars at from 17 to 27° failed to germinate, as did 

 all of those placed in water. Those placed on the upper surface of leaves, 

 kept at from 15 to 32° temperature and from 55 to 85 per cent of humidity, 

 showed no germination in 6 days ; but spores placed on a watch glass under a 

 bell jar in a very moist atmosphere at from 20 to 35° and watered every 2 to 7 

 hours germinated in from 2 to 4 days, but after 6 or 7 days no further ger- 

 mination occurred. It is inferred from these tests that the power of germi- 

 nation is retained for about 5 days under conditions favorable to germina- 

 tion, but that it is lost very quickly in a less moist atmosphere, supposedly 

 because of desiccation ; that it is the occurrence simultaneously of favorable 

 conditions of temperature and moisture that is to be feared; and that it is at 

 such times that treatment should be employed. 



Infection experiments with mildew in Hungary, P. Laelte {Rev. Vit., 37 

 (1912), No. 951/, pp. 416-'fl8). — A resume of an article already noted (E. S. R., 

 27, p. 47). 



Anatomo-pathological investigations on roncet, A. Biasco {Ann. R. Scuola 

 Sup. Agr. Portici, 2. ser., 9 {1909), Art. 15, pp. 1-9). — A brief account is given 

 of the anatomical alterations marking the progress of this disease. 



The Panama disease of bananas {Agr. Neivs [Barbados], 11 {1912), Nos. 

 260, pp. 126, 127; 261, pp. U2, J^S).— This gives a summary of knowledge re- 

 lating to some of the diseases of the banana and particularly that known as 

 the Panama disease. 



It is thought that there are probably two distinct diseases which affect the 

 vascular bundles, and therefore the water supply, of certain varieties of plan- 

 tains and bananas. The first is the Moko disease, which is attributed to 

 Bacillus musce, while the second is designated as the Surinam Panama disease, 

 caused by Leptospora musce. In addition it is stated that possibly the Panama 

 disease of Central America is distinct from the above. 



