THE CONTROL OF INJURIOUS INSECTS 39I 



Sulphur-soap Mixture (for Red Spider). — Prepared by dissolving 

 I lb. laundry soap in 8 gal. water and adding 3-^ lb. flowers of sulphur. 

 The under side of the leaves should be sprayed. 



{c) Kerosene Emulsion. — A soap emulsion of kerosene has for 

 many years been used against aphids and other sucking insects. It 

 is prepared by dissolving 3^^ lb. of soap in i gal. of warm water, and 

 adding 2 gal. of kerosene to the hot soap solution. The whole is 

 then agitated until a creamy emulsion is formed. This stock solution 

 when properly made keeps indefinitely. When required for use the 

 stock solution is diluted with 10 times its volume of water. 



{d) Tobacco Decoction. — A strong decoction of tobacco stems or 

 leaves is an excellent remedy against aphids, either in the field or 

 in the greenhouse. The decoction is an extract and is made by 

 steeping refuse tobacco in warm water for several hours until a deep 

 brown liquid is obtained. Two pounds of tobacco are treated in 2 gal. of 

 water and afterward made up to 5 gal. It is a safe remedy. 



Several tobacco preparations are now on the market, the most 

 valuable for orchard spraying being "Black Leaf 40." This concen- 

 trated extract contains 40 per cent, nicotine sulphate and is usually 

 diluted with water, i part to loco, when used against plant-lice and 

 other sucking insects. It can be safely used with lime-sulphur, ar- 

 senate of lead or soap solutions. 



"Nico-fume" contains 40 per cent, nicotine sulphate and is much 

 used in greenhouses by vaporizing it at the rate of 3^^ oz. to 2000 cu. ft. 



Tobacco papers are also used in greenhouses. Dense fumes are 

 given off when they are ignited. 



{e) Miscible Oils. — Certain proprietary mixtures containing mineral 

 oils in combination with a small quantity of vegetable oil and some 

 alkali to make them miscible with water are valuable in the control 

 of scale insects. Reliable market preparations are more satisfactory 

 than those made at home and less likely to be injurious to the trees. 

 There is always a certain amount of risk in using these oils, but the 

 danger is lessened if they are used on dormant trees in line weather. 

 The more reliable brands are "Scalecide," "Target Brand," " Orchard 

 Brand" and ''Kil-0-Scale." 



(f) Pyrethrum. — Pyrethrum, known also as Buhach, Persian and 

 Dalmatian insect powders, and by other trade names, is used fre- 



