472 INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



ROSIN WASH. 



Though not a true emulsion and fast losing prominence as a spray, 

 this wash is included here because of its value as a spray and dip for 

 plants with tender foliage. 



Rosin 10 pounds 



Caustic soda (76 per cent) 3 pounds 



Fish oil 1£ pounds 



Water 50 gallons 



Put oil, rosin and a gallon of water in an iron kettle and heat until 

 the rosin is softened; add the caustic soda (dissolved in a small amount 

 of water) and stir thoroughly, after which add enough water to make 

 fifty gallons of spraying material. 



This wash is only effective for young scale insects, plant lice, or 

 other soft-bodied insects. 



SOAP WASHES 



A simple and easily prepared spray for use in small gardens is 



made from soap as follows: 



Whale oil or hard laundry soap 1 pound 



Water 5 gallons 



The soap is first dissolved in a small amount of hot water and the 

 remainder added afterward. This spray will not injure tender plants 

 or foliage, and is recommended only for young scale insects, plant 

 lice and other soft-bodied insects. 



SOAP POWDER 



Among the recent commercial insecticides is a soap powder which 

 readily dissolves in hot or cold water and has very good insecticidal 

 powers. The amount of dilution varies with the product, but is usually 

 1 pound to 5 or 6 gallons of water or as stated on the container. 



TOBACCO DECOCTIONS 



For soft-bodied insects in greenhouses, conservatories, or on house 

 plants, as well as for plant lice, leaf-hoppers and other similar insects 

 in the open, the tobacco decoctions are invaluable because they do not 

 injure the foliage and give excellent killing results. 



Home-made Extract 



Tobacco leaves or stems 1 pound 



Water 4 gallons 



Steep the tobacco in the hot water and apply directly. 



Commercial Extracts 

 The extract containing 2J per cent nicotine should be diluted to 

 sixty parts of water. The extract containing 40 per cent nicotine, 

 should be diluted from one to one thousand parts or one to fifteen 

 hundred parts of water. 



DUSTS 



A number of valuable insecticides are applied dry as dusts. We 

 have already referred to Paris green and lime as being used in this 



