15-2 insp:cticides, fungicides, and weed killers. 



making injections round an infested stock, amounting in all to 350 cubic 

 centimetres, of a solution of 23^ B. diluted with 7 litres of water [twenty 

 times its volume]. The result was perfect on the upper roots but not 

 complete on the deep roots. 



Aphides (naked plant lice). — Many observers have recommended 

 2-4 per cent solutions of calcium monosulphide and even the same 

 product in the form of powder as a specific against green lice. 



Ap]iis Per niece, Sulz, which is destroyed at the same time as the 

 leaf curl {Exoascus deformans) by a 4 per cent solution ; likewise the 

 Aphis Oxyacantha, Koch, which causes the cloque of the hawthorn ; 

 Aspidiotus perniciosus, Comstock (San Jose louse) ; Aspidiotus Aurantii, 

 Maskell (cochineal of the orange). The Canadian Government advises 

 for the destruction of these dangerous cochineals a bouillie consisting 

 of 18 lb. of slaked lime, 18 lb. of sulphur, and d\ oz. of blue vitriol in 

 10 gallons of water. For the same purpose there is used in California 

 a bouillie composed of 6 lb. of slaked lime, 3 lb. of sulphur, and 2 lb. of 

 common salt (the latter added at the moment it is to be used) in 10 

 gallons of water. This bouillie, it appears also, kills the woolly aphis. 

 According to the researches of Coquillet these two bouillies even used 

 of double strength are not capable of entirely freeing the trees from 

 their parasites. They only destroy 50 per cent. Mohr likewise found 

 these bouillies incapable of replacing more active ones, and Franck and 

 Kruger regard this means as insufficient to combat the different species 

 of cochineal. Garrigou found that calcium sulphide spread in fine 

 powder on the young moving lice followed by spraying with water 

 very effectual. Calcium sulphide in powder is a specific for the de- 

 struction of acari against which it yields perfect results. 



Tetranchus telarius (red spider, saw-fly). — Calcium sulphide may 

 prevent the premature fall of the leaves produced by the saw-fly ; it 

 also prevents the erinoses produced by the Taphrina, Fr., Erinemn, 

 Pers., and Phylleriuni, Fr. ; it also destroys the Fhytoptides which pro- 

 duce galls. As a preventive against these diseases spraying round 

 the plant and on the branches must be advised in winter after the fall 

 of the leaf and in spring before the opening of the buds. Coating the 

 tree wath a strong bouillie so as to cover all the buds occupied by these 

 parasites is still more efficacious. The U.S.A. Minister of Agriculture 

 advises to destroy Eriopliyes Bibis, Nal., syn. PJiytoptiis Ribis, Wester 

 (currant gall mite), and Eriophyes Vitis, Land., syn. Phytoptits Vitis, 

 Land, (erinosis of the vine), to use a bouillie consisting of 6 lb. 

 of lime and 6 lb. of sulphur in 100 gallons of water. To increase the 

 effect of the calcium sulphide 124^-25 lb. of soft soap may be added. 

 The milk of lime is boiled with the sulphur and the soft soap dissolved in 

 water added. Miss Ormerod (the late) and also Debray greatly recom- 

 mend calcium bisulphite and found it superior to sulphur. Taschenberg 

 finds that a little alum renders its solutions more active. 



45. Calcium Chloride, CaCl ,. — Preparation. — By treating marble 

 with hydrochloric acid. Tlie crystals of CaCl.,6H.,0 thus obtained are 

 heated to igneous fusion ; the mass is then cooled on a smooth surface 

 on which the chloride solidifies in white flakes with a crystalline 

 fracture. 



