NOTES AND ABSTRACTS, 



295 



Bordeaux Mixture, Points in the Preparation of. By W. Kelhofer 

 (Intemat. phytopath. Dienst. vol. i. No. 3, 1908, p. 65). — The character 

 and action of Bordeaux mixture depend on the quality of the materials, 

 the quantities of each used, and the method of preparation. 



The greater the amount of lime used, the sooner the precipitate loses 

 its flocculent nature and the more easily it is washed off the foliage, 

 but if only the amount of lime theoretically required is used there is a 

 danger of the copper soon becoming soluble and washing off. Hence to 

 prevent mechanical washing off and to retard the solution of the film of 

 copper salt, it is best not to use the mixture in a neutral condition, but 

 to use excess of lime, the amount depending on the kind, intensity, and 

 frequency of the prevalent rains in a given district. The solution should 

 be mixed cold, and the copper sulphate and the lime should each be 

 diluted as far as possible before mixing, i.e. the copper sulphate should 

 be dissolved in half the total quantity of water that is to be used and 

 the lime mixed with the other half. The copper sulphate solution 

 should be poured into the milk of lime slowly, and not vice versa. The 

 mixture is almost as good if the milk of lime is poured quickly into the 

 copper sulphate solution, but it is difficult to do this, and the former 

 method works best in practice. Certain additions are advantageous — in 

 particular, sugar. In France, sugar in large quantity was formerly 

 much used, but Kelhofer finds that a very small quantity is all that is 

 necessary, the actual amount depending on the quantity of lime used. 

 In practice with the usual 2 per cent, formula, 50 grams of sugar to each 

 2 hectolitres is suitable. The sugar acts as a preservative (it must be added 

 at the time of mixing, or at least within twenty-four hours of this), and 

 when it is used, the whole amount of mixture required for one season 

 may be prepared at one time and used when required. — G. H. P. 



Bracken as Litter. By E. J. Russell, D.Sc. (Gard. Mag. 2881, 

 Vol. lii. p. 44, and 2882, p. 71 ; January 16, and 23, 1909).— 

 The value of bracken for litter as compared to straw, its composition 

 before use and after as manure is carefully explained, and the results of 

 analysis and actual trial given. The author states that bracken contains 

 three times as much nitrogen, and as much phosphoric acid as straw, 

 but less potash. Its manurial value is about 50 per cent, higher than 

 that of straw. It possesses greater absorbing power than straw, but is 

 much inferior to peat moss. As a manure its decomposition is slow, 

 which renders it more effective on heavy clay soil. — E. B. 



Cabbage Bug 1 , The Harlequin. By F. H. Chittenden (U.S.A. 

 Dep. Agr., Bur. of Entom., Circ. 103; June 1908 ; figs.). — This insect 

 (Murgantia histrionica Hahn.) causes the leaves of cabbage and other 

 crucifers to wilt by piercing the veins and sucking the sap. The adult 

 insect is red and black and quite conspicuous. It is native in Mexico and 

 Central America, and is spreading northward, where it is likely to do great 

 damage until adverse climatic conditions check its progress. It is recom- 

 mended to plant early crops of rape, radish, or mustard that would attract 

 the insects, and then to destroy these by means of hand torches, etc. 



F . J. C. 



