402 PEAR GROWING IN CALIFORNIA. 



liquid 10 gallons of water. For summer use on pear trees it should not 

 be used stronger than 1 gallon of lime-sulphur to 35 gallons of water. 



No. 2. Lime-Sulphur — Homemade. 



Stone limfi 80 pounds 



Sulphur 60 pounds 



Water ^ 200 gallons 



Preparation. 



Bring about 50 gallons of water to a boil in some suitable vessel, 

 or a suflficient amount for slaking the 80 pounds of lime. Add the 

 sulphur and mix as well as possible with the water. When the water 

 is hot, carefully put in the lime, which will slack almost instantly 

 with the generation of a great amount of heat. This is desirable, as it 

 helps effect a combination of the lime and sulphur immediately. The 

 mixture must be boiled for at least 45 minutes. When finished, 

 the liquid is a bright red color, often turning olive green upon further 

 boiling. There is no danger of boiling too long, but on the other hand 

 too little boiling may be responsible for a poor product. Dilute with a 

 sufficient quantity of cold water to make 200 gallons of the spray. 

 Lime sulphur is one of our best insecticides as well as fungicides. 



No. 3. Nicotine (Tobacco Decoction, Sulphate of Nicotine, Tobacco Dust, etc.). 



For the various plant lice which affect pears there is nothing better 

 to apply during the summer season than nicotine, commonly used in 

 the form of a sulphate. It is sold under the names of nicotine sulphate 

 and Black Leaf "40." It is generally applied at the strength of 1 part 

 of water to 1,000 parts of nicotine sulphate. The addition of 3 pounds 

 or more of soap (whale oil or other good liquid fish oil soap is desirable) 

 to 100 gallons of the diluted spray adds to its efficiency. In combination 

 with distillate emulsion, 3 per cent strength, it is used for the control 

 of pear thrips. A decoction of tobacco is made by steeping stems and 

 leaves in water about the boiling point; it must not boil as nicotine 

 volatilizes readily. Tobacco dust very finely ground is used for root 

 forms of aphids and is sometimes dusted on trees infested with plant 

 lice. 



No. 4. Kerosene Emulsion. 



Water 1 gallon 



Kerosene 2 sallons 



Hard soap 1 pound 



Preparation. 



Bring the gallon of water to a boil and dissolve the soap in it. While 

 hot add the kerosene, agitating the mixture violently for fifteen min- 

 utes or more. A cream-like emulsion should be formed, which will mix 

 readily Avith cold water. A .stock solution, containing 66^ per cent oil, 

 is obtained by this process and may be diluted to any desired strength' 

 Larger quantities are prepared by using the same materials in a like 

 proportion. A simple method for diluting to any desired strength is as 

 follows: Divide 200 Ijy the per cent desired and subtract 3. This will 

 give the amount of water necessary to add to each 3 gallons of stock 

 solution for the desired per cent. For example, a 15 per cent solution 



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