24 MISC. PUB. 52 6, U. S. DEPT. OF AGRICULTURE 



tonite are most likely to give this effect. Those who experience 

 difficulty of this kind should protect themselves by the use of a 

 respirator provided with pads saturated with citric acid. 



Very acute illness can be caused by the absorption of nicotine 

 through the skin. If concentrated solutions of nicotine are 

 spilled on the skin, they should be immediately washed off with 

 water. The operator should not continue working in outer cloth- 

 ing which has become wet with nicotine-containing sprays, as the 

 body will take up the nicotine from the clothing. 



NICOTINE BENTONITE 



Bentonite has the property of combining with nicotine to form a 

 compound more resistant to weathering than other nicotine prepara- 

 tions, hence it has been used extensively on apples during the past 

 few years as a substitute for lead arsenate in the control of the codling 

 moth, and to some extent on grapes for the control of the grape berry 

 moth. 



Nicotine when combined with bentonite may persist on fruit for 

 2 or 3 months, though in amounts too small to be toxic to man. 



Tank mixtures are the cheapest and most effective but are more 

 adhesive and may leave visible bentonite residues at harvest. 



An effective tank-mixed spray for use on apples during the cover 

 spray period consists of — 



Nicotine sulfate (40 percent) 1 pint. 



Wyoming bentonite 5 pounds. 



Crude raw soybean oil 1 quart. 



Water 100 gallons. 



Place about one -third of the water in the tank, add the nicotine 

 sulfate, then add the bentonite slowly with strong agitation, followed 

 by the soybean oil and the remainder of the water. Continue the 

 agitation while spraying. 



Proprietary nicotine bentonites are obtainable on the market. 



NICOTINE DECOCTIONS (HOME-MADE) 



For many years gardeners have used tobacco decoctions prepared 

 in different ways. The most common method is to soak tobacco stems 

 or high-grade tobacco refuse for 24 hours, stir occasionally, and use 

 the liquid. It requires 1 pound of stems for each gallon of water to 

 make a satisfactory spray. If high-grade refuse is used, less is re- 

 quired — in some instances only one-fifth to one-tenth as much refuse 

 as stems. The commercially prepared nicotine extracts have largely 

 replaced this method of obtaining nicotine ; see Nicotine, page 23. 



Tobacco stems are burned in greenhouses to produce smudges to 

 kill aphids and whiteflies, but this method is not used very much 

 nowadays. 



NICOTINE DUSTS 



Nicotine dust is the name commonly used to designate a dust made 

 by combining nicotine with a powder (see Diluents for Dusts, 

 page 11). Ground tobacco, which also contains nicotine, is usually 

 called tobacco dust ; see page 37. The former has the advantage that 



