46 INSECTICIDES AND SPRAYING 



made from fish oil. Ordinary laundry soap and ivory soap are both 

 efficacious against lice and harmless to foliage or fruit. 



A five-cent cake of ivory soap dissolved in five or six gallons of 

 hot water or one pound of laundry soap in the same amount of 

 water is an excellent remedy for plant lice, and will not injure the 

 most tender foliage. It is best used warm, and a little tobacco 

 decoction, either made from stems or purchased, if added to the 

 soap solution increases its efficiency. 



Tobacco Extracts. While a fairly efficient extract may be made 

 by steeping tobacco stems or other waste forms of tobacco, it is 

 better to rely upon the commercial extract at present on the 

 market. " Black Leaf 40," a nicotine sulfate solution, gives excel- 

 lent results. The commercial form may usually be used in 

 place of the patent preparation. It is expensive, but can be 

 effectively used hi such extreme dilution that the final cost is 

 slight. For example, one or two tablespoonfuls in a gallon 

 of water are most effective against plant lice, and if this solution is 

 poured several times at intervals around the base of melon vines 

 it forms an exceedingly helpful remedy for the larvae of the striped 

 cucumber beetle working on the roots. 



Nicofume is another tobacco solution. It is vaporized in 

 greenhouses; and a prepared paper (Nicofume paper) is burned as 

 a fumigant against lice on melons and in greenhouses. It is pre- 

 pared by soaking porous paper in tobacco extract or nicotine 

 sulfate. After drying it may be burned, causing the desired fumes. 



Tobacco Dust. This is finely powdered product, used on young 

 radishes against root maggot, and on dahlia and aster buds against 

 tarnished plant bug. It is also of practical use in greenhouses. 



Flowers of Sulfur. This material is dusted on steam pipes in 

 greenhouses, but is only fairly effective against the " white-fly." 

 Mixed with air-slaked lime it is used for control of red spider 

 and mite. 



Pyrethrum, Buhach, Persian Insect Powder. This is made 

 from the pulverized heads of a species of chrysanthemum. Must 

 be used when fresh to be effective. Harmless to human beings 

 and to foliage. It is either dusted on plants or steeped for 

 several minutes in water, one ounce of pyrethrum to three quarts 

 of water. 



Air-slaked Lime. This is an excellent and cheap deterrent and 

 insecticide for many insects. Dusted on leaves of fruit trees, it 

 is deadly to the leaf -eating "slugs." It saves to a large extent 



