72 COLOEADO POTATO- BEETLE. 



to induce a concert of action amongst agriculturists. This could 

 be accomplished by planting only the earliest varieties of pota- 

 toes. If this method were universally put in practice, there 

 would be no potatoes after mid-summer for the insects to feed upon, 

 and they would probably all perish from starvation. And even if 

 a 8:nall proportion of them should subsist upon other plants till 

 fall, they would be of too old a brood to survive the winter and 

 perpetuate the race another year. 



But it is now generally admitted that the most effective remedy 

 for the Colorado Potato-beetle, so far as human agency is con- 

 cerned, is the application to the vines of the poisonous substance 

 commonly known as Paris-green, and chemically designated as 

 the Arsenite of Copper. This substance proves fatal to the insects, 

 not by coming in contact with them, but by being eaten bj^ them. 

 Indeed, these creatures have a very pertinacious vitality under 

 all the ordinary applications which prove destructive to insects. 

 I have thoroughly sprinkled the infested vines with copperas water, 

 one ounce to the quart, ^7hich has been highly recommended ; 

 and with fish brine, one quart to two gallons of water, but both 

 applications hurt the vines much more than they did the insects. 

 I have also immersed the beetles in diluted carbolic acid, and then 

 rolled them over and over in Paris-green, and put them in a box, 

 and some of them were alive on the next day. Bat when this 

 article is eaten by them with the foliage, it proves speedily and 

 certainly fatal. 



The first time that I knew of this substance being used on a 

 large scale, was in the summer of 1869, by Mr. E. W. Grosvenor, 

 of Hastings, Minnesota. This gentleman used twelve dollars worth 

 of Paris-green, diluted at about the rate of one quarter of a pound 

 to half a peck of flour, and.saved his potato crop. Upon the older 

 vines it had to be repeated, but upon vines three or four inches 

 high, he thought it affected them in some way which rendered 

 them thenceforward repugnant to the insects. But upon this point 

 it is proper to remark that the^^testiraony is conflicting. Mr. Gros- 

 venor also mentioned the interesting incident that in stripping 

 the bark from some old fence posts in the winter time, near the 

 fields that had been infested by the bugs, he found thousands of 

 them, which had availed themselves of this shelter for the winter, 



