50 The Spraying of Plants. 



2. The application is repeated in four or five weeks. 



3. The mixture is applied within three to six weeks after the 

 second treatment. If the weather is inclined to be wet, a 

 shorter interval is allowed between the two. 



4. A fourth application is not regularly made. In case of a 

 wet season it is made three or four weeks after the third. A 

 fifth treatment is rarely thought necessary. 



Insecticides. 



The insecticides in use in France during these years are, with 

 few exceptions, still of the same general character as those used 

 in the past. Black soap was very commonly employed. It 

 was recommended, 1 in connection with amylic alcohol, for the 

 destruction of the "puceron lanigere" (woolly aphis). The 

 formula given is : 



Black soap 35 grams. 



Amylic alcohol 60 " 



Water 1 liter. 



Dissolve the soap in the water and then add the alcohol. The 

 material was applied by means of a broom or a syringe. The 

 alcohol was sometimes replaced by 10 percent of phenic acid, this 

 and the soap forming an emulsion. 



Other recommendations for the destruction of the same insect 

 have also been made. 2 In addition to the black soap wash are 

 mentioned : 



Aloes 4 grams. 



Water.. ..1 liter. 



Also, 



Oxalic acid 15 grams. 



Water 1 liter. 



And another, a commercial preparation : 



Insecticide Fichet 250-300 grams. 



Water 10 liters. 



* Jour. d'Ag. Prat. 1887, May 12, 680. * Ibid. June 30, 923. 



