DISEASES OF PLANTS. 155 



funjais. On this account it was found to r)e especially necessary to protect 

 the foliage with fungicides during the months of August and September. 



Experiments were conducted with different strengths of copper sulphate solu- 

 tions and Bordeaux mixture, and it was found that while weak solutions were 

 efficient in protectini; the leaves for a time against the invasion of the fungus, 

 the period of protection was nuich shorter than where stronger solutions were 

 emiiloyed. In a comparison of the efficiency of simple sohitions of copper 

 sulphate a 1 per cent solution upon the leaves remained protective for 28 days, 

 while a 2 per cent solution remained efficient for 48 days. A solution con- 

 taining about i of 1 per cent copper sulphate was effective for only 7 or 8 days. 

 In practice it was found that spraying thoroughly with a 2 per cent solution 

 late in July will oi'dinarily protect vines against the downy mildew throughout 

 the remainder of the season. 



The resistance of table grapes to downy mildew, K. Salomon (Rev. Vit., 

 21 (1907), Xos. 701. lip. 576-578; 703, pp. 630-633). — A report is given of inves- 

 tigations to determine the relative susceptibility of varieties of table grapes 

 to mildew. In all ISO varieties, represented by over 800 specimens, were ob- 

 served during the years 1902, 1903, 1904, and 1905. The grapevines were all 

 in the same field, were sprayed 3 times with Bordeaux mixture, and were 

 subjected to similar conditions throughout. In reporting upon these different 

 varieties the author adopted a scale of resistance, and while some differences 

 were noted due to slight attacks of the fungus on some of the species, yet in 

 general the relative resistance remained the same. The relative resistance 

 of the different varieties is shown in tabular form. 



A new treatment for downy mildew, E. Chuard (Chroii. Ar/r. Vatifl, 20 

 tino7). .A'o. 9. pp. ISI-ISS). — In reporting upon experiments for the control of 

 the downy mildew of grapes, the author gives an account of the use of a new 

 fungicide which he claims has proved very efficient. This fungicide is made by 

 dissolving 200 gm. of copper oxychlorid in a hectoliter of water, with which 

 the vines were given 5 applications. The copper oxychlorid is said to be an 

 intermediate product in the manufacture of copper sulphate and consists of a 

 ciimbination of chlorate and oxid of copper. This fungicide does not appear to 

 injure the foliage even when used in very strong solutions. It is sufficiently 

 notic("al)lo when sprayed ui)on foliage and appears to be exceedingly adhesive. 



A disease of larch trees in Jura, L. Mangin and P. Hariot (BiiI. Trimest. 

 Soc: Mijcol. France, 23 (1907), No. 1, pp. 53-68, figs. 9).— A description is given 

 of a disease of larch trees which is characterized by the orange-red color 

 assumed by the leaves of diseased trees. These, standing out against the uni- 

 form green color of the other trees, make them very conspicuous objects. This 

 disease has been attributed to the fungus Hypoderma iierviscginnn, but the 

 authors have found a number of species of fungi attacking the foliage, the more 

 impdrtant of which ai*e noted in a preliminary account (E. S. K.. 18, p. G-IO). 

 In addition to these fungi a number of others seem to occur quite uniformly 

 upon the leaves, so that the authors are unable to decide what particular 

 organisms are the cause of the disease. It is believed, however, that Rhizosplwra 

 ubKlin. is one of the most prominent in causing the trouble. 



A disease of maple trees, F. von IIohnel (O.stcrr. Bot. Ztschr.. 57 (1907). 

 No. 5. pp. 177-181). — A disease of the maple, Acer campestre, is described which 

 is attributed to the fungus PoljiponiK rndlaiust. The author points out resem- 

 Idances l)otween this fungus and a number of other allied species and gives a 

 technical description of it. 



The leaf blotch of maples (.lour. Bd. A;/r. ILondon]. 1 ', (1907), No. 2, pp. 

 106, 107. pf/. /).— Descriptive accounts are given of two forms of leaf blotch 



127CG— No. 2—07 5 



