298 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 14 



at the rate of from 5 to 10 lbs. per acre might well be made. This is 

 about as thinly as the average person can apply it by hand and cover 

 the ground uniformly, 



Comparative Value of Poisons 



The optimimi strength of the various arsenicals in poison bran mash 

 and the optimum rate of application in the field, having been deter- 

 mined to the writers' satisfaction, it was decided to learn, if possible 

 which arsenical is most effective in grasshopper control. According- 

 ly a series of experiments were outlined whereby the three common 

 arsenicals, namely Paris green, white arsenic and crude arsenic, were 

 run under similar conditions and in each case at their optimum strength 

 and rate. Quarter acre plots were treated with the various mixtures 

 and the hoppers swept therefrom handled as has been previously ex- 

 plained. 



The following table which includes the results of 8 series of experi- 

 ments in which the three arsenicals were run, shows the date, poison, 

 number of hoppers swept, number of hoppers which died, the number 

 of hoppers remaining alive, and the percentage of kill. 



Table IX 



Totals 



1715 



887 



828 



