INSECTICIDES AND FUNGICIDES 193 



slaking lime, enough water being added to make a pasty mass. 

 The barrel should now be covered, in order to retain the heat, 

 and the contents should be occasionally stirred. The time 

 required varies with the quality of the lime; if the lime acts 

 quickly, five to ten minutes will be sufficient, while if it acts 

 slowly, fifteen minutes may be necessary. It should not be 

 allowed to stand too long, because it may, in that case, be inju- 

 rious to foliage. Now add a little water, stirring the mixture 

 while it is being poured in. Then add enough Avater to bring 

 the total up to fifty gallons. In applying the spray it is neces- 

 sary to have a good agitator in the sprayer. 



Miscible oils {oils that will mix ivith water). — There are 

 several oils on the market that are miscible with water. These 

 make a good wdnter spray for scales, and are also excellent 

 summer sprays against the same insects. Great care, however, 

 must be taken to obtain the right dilution, as per directions given 

 on container, or burning of the leaves will result. 



Paris green. — This is the old stand-by, and is still used by 

 many where an arsenical insecticide is necessary. Our experi- 

 ments on orchard trees, and other reports, indicate that arsenate 

 of lead is better in every respect ; although our potato expert at 

 the Experiment Station, Mr. Kohler, who has experimented wdth 

 many of the stomach insecticides for potato beetles, finds Paris 

 green the most satisfactory for these pests. It is generally used 

 at the rate of one pound to fifty gallons of spray. In using 

 always first make a paste of the Paris green and water, and then 

 add to the spray material. If water alone is used, two to three 

 pounds of stone lime should be added. If Bordeaux mixture is 

 used, the addition of lime is not necessary. 



Potassium sulphide {Liver of sulphur). — 



Formula : 



3 to 5 ounces of potassium sulphide. 

 10 gallons of water. 



This is used in place of Bordeaux, to avoid spotting of foliage 

 and fruit. It is considered to be especially effective against 

 powdery mildews, such as the gooseberiy mildew. It is also 

 quite extensively used in greenhouses and on shrubbery. 



Pyrethrum or insect powder {Persian Insect Poicder, Dalma- 

 tian Insect Powder or Buhacli). — This is a powder from the 

 ground-up flowers of the pyrethrum plant. It is a contact 

 insecticide, and is used against fleas, cockroaches, etc. If the 

 powder is burned in a room, the fumes will destroy mosquitoes 

 and flies. Purchase only when warranted fresh, and then, when 

 in sealed cans. 



