INSECTICIDES 489 



to each 100 gallons to make the mixture spread and stick 

 better. 



Nicofume is a tobacco extract containing 40 per cent of nico- 

 tine in the volatile form. It is intended primarily for use in 

 greenhouses. Strips of paper soaked in this preparation are 

 smudged in greenhouses to destroy aphids. 



Tobacco is also used in the form of dust for the same purpose. 

 It is especially valuable against root-Hce on asters and other 

 plants. Tobacco extracts can be made at home by steeping 

 tobacco stems in water, but as they vary greatly in nicotine con- 

 tent and are sometimes Ukely to injure tender foliage, it is better 

 to buy the standardized extracts. 



Bordeaux Mixture 



Bordeaux mixture has been for many years the most widely 

 used fungicide, but has now been replaced by the dilute lime- 

 sulfur solution for orchard spraying in many parts of the country, 

 owing to the serious foliage injury and russetting of the fruit 

 often caused by its use. In addition to its fungicidal properties 

 it also acts as a deterrent to many insects, especially flea beetles. 

 Either arsenate of lead or Paris green may be used in combina- 

 tion with it. 



Bordeaux mixtiu'e is prepared by mixing a solution of copper 

 sulfate (CUSO4) and milk of lime (Calcium Hydroxide) accord- 

 ing to the following formula : 



Copper sulfate 4 pounds 



Lime 4 pounds 



Water 50 gallons 



In some cases a weaker mixture is used, containing 3 pounds 

 of copper sulfate and lime respectively. These formulas are 

 often abbreviated thus : 4-4-50 and 3-3-50. 



When needed in large amounts Bordeaux mixture is most 



