83 



yard. Calcium bicarbide may be used instead of carbon bisulphide 

 against root-insects, at the rate of 2| oz. per tree, placing it in three 

 portions in the form of a triangle at the base of each, at a distance of 

 half a yard from the trunk. As this mixture gives off acetylene, it 

 should be buried 18 inches below the surface ; 2 lb. of bicarbide 

 usually gives off 300 litres of gas. 



Benzine, as well as carbon bisulphide, is used to kill the larvae of 

 insects that make galleries in tree-trunks. The entrance is opened with 

 a wire, and a little of the liquid is placed inside, the hole being then 

 closed with wax. Lysol has also been successfully used against 

 Scolytids. A thick millc of lime is prepared and 5 per cent, lysol added. 

 This is washed over the trunk and the larger branches in August, and 

 is renewed in spring. 



Bordeaux mixture is made from copper sulphate, 4 lb. ; recently 

 slaked and sifted lime, 8 lb. ; water, 20 gals. The copper sulphate is 

 dissolved in 10 gallons of water ; in another vessel a milk of lime is 

 made with the 8 lb. lime and 10 gals, water ; when the sulphate is all 

 dissolved, it may be mixed with the lime. This is done in a separate 

 vessel, the milk of lime and the sulphate being added gradually, in 

 equal proportions, stirring all the time. Wooden vessels must be used. 

 If the lime used is not of good quality, it may give an acid reaction ; 

 the mixture must therefore be tested and more lime added if necessary. 

 This mixture may be used in combination with arsenical salts. 



The following formulae for formalin solutions for disinfecting potatoes 

 before sowing are given : — I : Formalin, 40 per cent, strength, 1 lb. ; 

 water, 20 gals. ; the potatoes should be submerged for 1| to 2 hours. 

 II: Permanganate of potash, 11 J oz. ; formalin, 1|- pints. This is 

 sufficient to disinfect 11 cubic yards, the potatoes remaining submerged 

 for 48 hours. 



Semichon (L.). Emploi des Composes Arsenicaux en Viticulture. 



[The use of Arsenical Compounds in Vinevards.] — Rev. VUicuUare, 

 Paris, xlv, no. 1169, 23rd November 1916, pp. 338-341. 



According to regulations issued uj) to 15th September 1916, arsenical 

 compounds intended for use against insects harmful to vines can be 

 employed only if insoluble [see this Review, Ser. A, v, p. 47]. They may 

 be used only from the beginning of the growing season up to the end of 

 the flowering season. The storing and handling of these jjroducts in 

 vine-growing operations are subject to very severe and exacting 

 regulations and any offence against these is punishable by fine or 

 imprisonment or both. 



It is realised by vine-growers that owing to the conditions 

 under which these compounds were formerly sold, these regulations 

 are necessary, though, in spite of the large quantities dealt with, 

 accidents were extremely rare. 



The arsenical compounds generally used in vine-growing may be 

 divided into two groups : — The arsenates of soda, lime, copper, zinc 

 and lead, used from the bursting of the leaf-bud until the flowering 

 season, and the compounds having as a base arsenite of soda or arsenic 

 acid, used generally during the winter, principally against Sparganofhis 

 pilleriana, and to a certain extent against Clysia ambiguella and PoJy- 

 chrosis botrana. 



((■346) c2 



