REMEDIES AGAINST SCALE-INSECTS. 90 



If used in sufficient strength to kill Scale- insects, the hands and arms 

 must be protected from tbe liquid bj' rubber gloves, and care must also 

 be bad to avoid inhaling the i)oisonous gases exhaled. 



In its active state tbe preparation is a depilatory, and by applying it 

 as a paste tbe hair upon any part of the body may be reduced to gela- 

 tine and removed. 



Bisulphide of Carbon. — The few trials made of this substance have not 

 given very satisfactory results, and additional experiments are needed 

 to determine whether it can be safely and economically used as a remedy 

 for Scale-insects. Although a powerful insecticide, the extreme severity 

 of Us action upon the trees and tbe cost of the materials detract greatly 

 from its value. It is an exceedingly volatile and explosive liquid, which 

 must be kept in tightly-sealed glass bottles, and the fumes cannot be. 

 inhaled by man or other animals without danger. The bisulphide may 

 be emulsified with oils and milk or soap, but not more than three or 

 four fluidounces should be contained in each gallon of the diluted wash. 



Api)endix 11, table 5, gives the result of some experiments with bi- 

 sulphide of Carbon. 



Sulphurio Acid. — A single experiment with sulphuric acid, 4 fluid- 

 ounces in G quarts of water, applied with a brush as far as possible to 

 all parts of a young tree, killed nearly all the Scale-iusects, and very 

 nearly killed the tree. The bark was blackened but not destroyed, and 

 nearly all the leaves dropped. The tree, however, slowly recovered. 



Sidpkate of Iron. — This substance is exceedingly injurious to vegeta- 

 tion, but is, nevertheless, a very common ingredient of patent and pro- 

 prietary remedies. Its presence can bo detected by the inky-black or 

 brown stains which it forms in the substance of the leaves and the rind 

 of the fruit. 



It does not affect the Scale-insect except by destroying the vegetable 

 tissues from which it gets its subsistence. 



Ammonia. — With this in a pure state no experiments have been made, 

 but to its presence in fermenting urine is probably due tbe insecticide 

 properties of the latter. Applications of urine have often been recom- 

 mended as a remedy tor scale, and are certainly not \\ itbout value, but 

 if allowed to stand and ferment, and especially if soot or other ;U)sorb- 

 ents of the ammonia are mixed with it, it becomes highly injurious to 

 vegetation, and if applied at all should be greatly diluted. A mixture 

 of soot and fermented urine applied undiluted to a small orange tree 

 effectually cleared it of scales, but very nearly killed the tree. 



SiUeote of 8oda. — This is a thick viscid liquid, sometimes sold as a 

 solid. It is readilj' soluble in water. When sprayed upon orange trees 

 it soon dries and forms a coating of gum which partially peels off, car 

 rying with it many of tbe old dead scales ami some living ones. When 

 applied in sufljcient strength it kills most of the Coccids, but does not 

 destroy the eggs. It injures the plant more than kerosene, with which 

 it cannot be compared in elficiency or cheapness. The preparation is 



