NICOTINE SULFATE 423 



nearly cover with water. As the heat develops, the sulfur is added, 

 care being taken to avoid any lumps of sulfur. Stir constantly. 

 As much as three or four gallons of the water may be added 

 gradually. The mixture should boil for several minutes. Then 

 more water is added until the solution is cooled. The remainder 

 of the water is added to complete the above formula, 8-8-50. 

 This is used as a summer spray to prevent disease and to control 

 scale insects, particularly on the stone fruits, such as peaches, 

 plums and cherries, but it is also used effectively against diseases 

 of leaves and fruit on the apple, pear, and others. 



Fish Soaps. Whale-oil soap is used in spraying for plant lice. 

 It is effective against soft-bodied insects. One pound of the soap 

 to six gallons of water is effective. It is not injurious to the foliage 

 of plants. Although whale-oil soap solution was formerly used in 

 fighting scale insects, other remedies are now usually preferred, 

 i.e., miscible oils and lime-sulfur wash. 



Miscible Oils. There are several commercial products bear- 

 ing trade names which are made up chiefly of miscible or soluble 

 oils. These contain mixtures of petroleum or its products with 

 some vegetable oils, made " soluble " by the addition of an alkali 

 such as sodium hydroxide. This makes the oil combine readily 

 with water. Each of these preparations should be diluted accord- 

 ing to the directions ; the proportion is usually ten to twelve parts 

 of water to one part of the commercial mixture as a winter spray 

 against San Jose scale. Twenty-five to thirty parts of water are 

 used as a summer treatment for plant lice and other soft-bodied 

 insects. 



Tobacco Decoction. This is made by boiling tobacco stems 

 and other tobacco refuse in water, using one part to about two 

 gallons. Its strength may be varied according to the insects on 

 which it is used. Commercial preparations of uniform strength 

 are found in the market. 



Ground tobacco stems are often applied in dry form against 

 apple root aphis, or may be dusted upon leaves to drive away 

 'various insect enemies, as in the case of the tarnished plant bug 

 on melons and other vines. 



Nicotine sulfate under various commercial names is found in 

 the market. It contains the active principle of tobacco, and is 

 often very strong. "Black Leaf 40" is one of these preparations/ 

 which requires one hundred parts of water. In this strength it is 

 effective in spraying melon lice. 



