SOAP SOLUTIONS AND EMULSIONS. 331 



surface clean and neat ; the earth is then beaten, watering it if need 

 be. During the night the mole crickets dig new tunnels, which are 

 seen the next morning. The fresh tunnels are opened with the finger 

 and tepid soapy water poured in from a watering-can. 



Formica (ants). — Soap is used against ants infesting trees. 



Eriocampa adumbrata, Kl. (saw-fly of the slug-worm or slimy 

 caterpillar).— Nessler's insecticide (formula 7, p. 328) is an excellent 

 medium to kill the slimy caterpillar. 



Blissus leucopteris, Say. — This bug, injurious to gramineae, is 

 destroyed by spraying with soap solutions (Quaintance). 



Phyllobius ohlongus (coleoptera injurious to the pear). — Horfer 

 recommends abundant spraying with a 1 per cent solution of soap. 



AphidcB, (plant lice). — To destroy green lice in general Ducloux 

 recommends two bouillies : (1) Soft soap 5 lb., tar 15 lb., water 2 

 gallons ; (2) Tobacco extract 2-3 gallons ; soft soap 5-10 lb., methyl 

 alcohol 1 gallon, carbonate of soda 5 lb., water 100 gallons. 



Aphis Papaveris. — Killed by a few sprayings with 5 per cent soap 

 solution (Noel). 



Aphis Bosce, L. (rose aphis). — Green lice, as well as all unprotected 

 lice, are readily destroyed by pure soap solutions and insecticide mix- 

 tures with a soap basis. Not being covered with a protective down 

 like the woolly aphis, and living on the surface of the plant organs 

 from which they draw their nourishment, they are far more accessible 

 to insecticides, and resist them less. The solutions should be diluted 

 so that neither the soap nor the insecticide injure the foliage. Solu- 

 tions of 2 per ceat of soap produce the desired eflect. Lowe considers 

 that 1-5 per cent of whale oil soap is better than all the other methods, 

 if used as a spray, as soon as the lice appear on the young leaves. 

 As winter treatment to kill the eggs or the adults in their refuge, a 

 50 per cent solution of soft soap may be used, according to Taschen- 

 berg. Many mixtures are recommended to replace solutions of pure 

 soap ; those consisting of quassia and tobacco, and diluted with water 

 so as to contain 1-5-2 per cent of soap, vide supra. Delacroix recom- 

 mends 1 lb. of carbonate of soda, 2 lb. of soft soap, in 10 gallons of 

 water. 



Schizoneura lanigera, Hausmann (woolly aphis). — Soft soap is used 

 alone and incorporated with insecticides to kill the woolly aphis be- 

 cause it peneti'ates the down of white wax which protects the adult 

 and allows the insecticide to act by contact. The U.S.A. Agricultural 

 Department recommends a 6 per cent solution of soft soap. Muhlberg 

 records the bad result obtained with a 7 per cent solution of soft soap, 

 whilst Goethe found a 5 per cent solution very efficient. The season 

 when the soap solutions are used evidently exercises an important in- 

 fluence that explains the different results obtained with the same 

 product, for it is asserted that the young larvae not coated with down, 

 hatched in November or December, are very sensitive to insecticides, 

 whilst the adults, owing to the agglomerations which they form, often 

 escape the action of the most energetic insecticides. It is thus well 

 to choose the most propitious time for treatment, November and 

 December. At that time they may be successfully destroyed by 



