June, "211 



FORD & LARRIMER: EFFICIENCY OF GRASSHOPPER BAITS 



295 



Apparently the higher strengths of Paris green do not give as good 

 results as the lower ones. The one pound formula gave the best kill, 

 being 84.5%, but the y^ lb. strength gave 79% kill, there being only 

 5K% difference. It would appear that the Yz lb. strength is probably 

 more efficient than the 1 pound, since a 5>^% increase in kill would 

 not warrant doubling the amount of Paris green at its present price. 



Table III White Arsenic (Bait applied Aug. 22). 



Totals 



1844 



1294 



The results of these experiments show the usual formulae which con- 

 tain white arsenic as the poisoning element are stronger than necessary. 

 Here K lbs. per 25 lbs. of bran gave the best kill, it being even better 

 than any of the higher strengths. The check hoppers showed a 5.8% 

 mortality during the six days of captivity. 



T.\BLE IV Crude Arsenic (Bait applied Aug. 27). 



Strength of crude 

 arsenic 



Total No. hoppers No. hoppers dying No. hoppers re- Percentage of kill. 

 swept maining alive 



Totals 



2381 



1449 



932 



