DISEASES OF PLANTS. 679 



growth of the fungus the amount of copper may he increased to f or 1 per cent. As 

 weak a solution as 0.25 may be used in dry climates or in regions relatively free from 

 the disease. 



Parasitic diseases of the vine, F. Gueguen (Les maladies parasitaires de In vigne. 

 Paris: Octave Doin, 1904, pp- VI-\-198, figs. 83). — After describing methods for the 

 examination of diseased vines, the author gives an account of the different plant and 

 animal parasites to which the grape is subject. Chapters are devoted to thediseases 

 caused by hacteria, fungi, and phenogamic parasites, as well as the various insects, 

 mites, spiders, nematodes, snails, etc., giving suggestions for the prevention of their 

 injuries. 



Canker of trees, F. Van Biervliet (Rev. Gen. Agron. [Louvairi], 13 (1904), No.9, 

 pp. 378-380). — A brief account is given of an attack of Nectria cinuahuriua on linden, 

 mulberry, ash, beech, and various other trees. 



A leaf fungus on Hevea braziliensis (Agr. Bui. Strait* and Federated Malay 

 Stales, 3 (1904), No. 8, pp. 308, 309). — The occurrence of a leaf fungus, which is 

 apparently related to the Uredinea?, is reported on leaves of Para rubber trees on the 

 Malay Peninsula. The effect on the host plant is briefly described, and from its 

 apparent serious nature the author recommends the removal of infected leaves and 

 spraying with Bordeaux mixture. 



Sulphur mixtures, E. Rabate (Rev. Vit., 22 (1904), No. 574, pp. 671, 672).— On 

 account of the extensive use of various forms of sulphur in liquid fungicides, the 

 author has investigated their preparation and concludes that it is possible to prepare 

 a stock mixture that can be used at any time. This is made by mixing into a thick 

 paste lime and sublimed sulphur, and covering the mixture with sufficient water to 

 prevent carbonization. When ready for use this can be added to a 2 per cent solu- 

 tion of copper sulphate, making a Bordeaux mixture with sulphur. This should be 

 made neutral, being tested with phthalin, helianthin, or other test papers. 



The sulphur when mixed with the lime is insoluble and acts in solution something 

 like fine sand, diminishing the adherents of the copper precipitates. < >n this account 

 this fungicide is less adapted to use in combating such diseases of vines as the black 

 rot or downy mildew, but for the powdery mildew it lias exceptional value. 



The use of indicators for testing copper fungicides, E. Rabate (Prog. Agr. 

 et Vit. (Ed. L'Est), 25(1904), No. 41, pp. 417-420) .—The author points out the 

 advantage of the use of indicators for testing Bordeaux mixture and other solutions 

 of copper, to determine when the mixture is neutral. For this purpose he gives the 

 results of comparative tests of helianthin, tournesol, and phenolphthalein. Of these 

 the author states that tournesol is a secret preparation of varying constitution, and is 

 not to be preferred over either of the others. 



For those who are not thoroughly conversant with chemical manipulations he rec- 

 ommends the employment of phenolphthalein when the solutions are known to be 

 but slightly alkaline, as this will prove of easy and satisfactory use. Helianthin is a 

 more sensitive indicator in the presence of carbonic-acid gas, which is given off by 

 the Burgundy mixture, and is an indicator which permits of more economy in the use 

 of basic products. This economy, which would be but slight in the case of the use i if 

 lime, is of sufficient importance to take into consideration when carbonate of soda or 

 ammonia is used. 



The efficiency of dilute Bordeaux mixture, G. B. Cucovicii (Bui. Agr. Algirie 

 et Tunisie, 10 (1904), No. 12, pp. 257-261). — For three years' the author has been 

 experimenting with dilute solutions of Bordeaux mixture in which the amount of 

 copper present has been reduced to 1 per cent or less, with the necessary lime to 

 make the mixture. 



This has been used in spraying for downy mildew of grapes, and the results show 

 that a 1 per cent solution is sufficiently strong for all purposes, even in rainy seasons. 



