REMEDIES FOR SCALE INSECTS 



177 



compounds. This is made by dissolving one-half pound soap in 

 one gallon of water by boiling. Remove from fire and add one 

 gallon of cheap kerosene. Churn by forcing through spray pump 

 and add fourteen gallons of water, mixing thoroughly. It should 

 be used at once. This spray is intended to be employed when 

 young scales are crawling over the trees. 



Fia. 196. The circular scale. 



Fumigation is, on the whole, more satisfactory than spraying 

 and is in more general use in citrus orchards. The chemicals 

 most commonly employed are cyanide of potash and sulfuric acid. 

 The most desirable proportions are one ounce of cyanide of potash 

 to two fluid ounces of commercial acid and four fluid ounces of water. 

 Canvas tents made of eight-ounce canvas should be used to cover 

 the trees. These may be rendered more impervious to gas leakage 

 by painting thoroughly with boiled linseed oil, or in other ways. 

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