4(j THE CANADIAN ENTOMOLOGIST. 



application of the mixture would cost from two to three dollars per acre, 

 exclusive of the labor. If the insect is very abundant, two or more 

 applications may be required, as exposure to wind and rain will eventually 

 remove the powder entirely from the leaves, rendering them liable to 

 further attacks. Some discretion should be exercised in selecting a 

 suitable time for using the mixture, which should not be applied during 

 high winds, or immediately before a rain storm. 



NOT DANGEROUS, IF CAREFULLY USED. 



As this mixture is of a poisonous character, ordinary care should be 

 used in handling it. to avoid inhaling much of the dust when applying it, 

 to wash the hands after each application, to keep it- out of the reach of 

 children., and to exclude live stock of all kinds from fields where the poison 

 is used. With these precautions no danger need be apprehended ; it does 

 not injure the leaves to any appreciable extent, unless very heavily applied, 

 and cannot possibly affect the potato itself. We make these remarks be- 

 cause we have met with several individuals who entertain a foolish pre- 

 judice against the use of this mixture, for fear that it might injure the 

 potatoes. 



OTHER REMEDIES TRIED. 



We did not content ourselves with the use of Paris Green only, but 

 experimented with as many other substances as the limited time at our 

 disposal would admit of ; and, although we would not have the results 

 here given to be considered as final in reference to the materials used, 

 we trust they will be of value as indicating the most promising remedies 

 for further trial. 



Arsenious Acid (Arsenic). — This chemical being much cheaper than 

 Paris Greeti i and more uniform in its composition, we hoped it would 

 have proved a practical and safe remedy. We tried it in the proportions 

 of half-ounce, one ounce and two ounces to a pound of flour ; and while 

 we are not prepared, from the few trials we have made, to entirely disap- 

 prove of its use, the results we have obtained point to the conclusion that 

 where it has been used in sufficiently large proportions to destroy the 

 insect, it has caused more or less injury to the leaves. In cases where 

 Paris Green is not obtainable, this might be used as a substitute, in the 

 proportion of one ounce to one pound of flour, which should always be 

 colored with some black powder, such as charcoal or black antimony, so 

 as to lessen the risk of accident from its use. 



