June, '21] FORD & LARRIMER: EFFICIENCY OF GRASSHOPPER BAITS 



293 



The following method was devised with the idea of making the ob- 

 servations more accurate. Quarter acre plots in an infested alfalfa 

 field were treated with the poison mash, care being taken to keep each 

 plot well isolated from the others to avoid error due to the hoppers 

 migrating from one plot to another. After allowing the hoppers to 

 feed on the poison mash in the field for several hours, but not long 

 enough for any of them to succimibto its effects, sweepings were made 

 with hand nets from the poisoned plots. In all of the following experi- 

 ments the poison bran mash was applied to the infested plots between 

 8 A.M. and 9 a.m. and the sweepings made between 2 and 3 p.m. of 

 the same date. The hoppers thus swept were placed in bags and 

 brought to the laboratory where they were put in out of door screen 

 cages with green com suckers for food. In each case a lot of hoppers 

 were swept from an unpoisoned area and run as a check. The cages 

 were examined daily and the dead hoppers removed and recorded. At 

 the end of six days the experiment was closed and the number of living 

 hoppers remaining in each cage recorded. Thus the number of hoppers 

 killed by each application of poison mash and the ntmiber of hoppers 

 surviving was accurately determined. 



Syrup Experiments 

 A series of experiments was planned whereby the percentage of kill 

 due to the various syrups was determined. Small amounts of poison 

 mash were mLxed with Paris green at the rate of one pound per each 

 25 lbs. of bran and the various s^Tups as shown in the following table. 

 Quarter acre plots were treated with these various mixtures as describ- 

 ed above, and the hoppers handled as previously explained. This ex- 

 periment was run in duplicate, the following table showing the com- 

 bined results of these two series. 



Syrup 



Table I (Poison mash applied Aug. 28). 

 Total No. hoppers No. dead hoppers 

 swept removed 



Black strap 2 qts. 



per 25 lbs. bran 



Black strap 1 qt. 



per 25 lbs. 



Dark Karo 2 qts. 



per 25 lbs. 



Dark Karo 1 qt. 



Eer 25 lbs. 

 ■ight Karo 2 qts. 

 Eer 25 lbs. 

 ight Karo 1 qt. 

 per 25 lbs. 

 Sorghum 2 qts. 

 per 25 lbs. 

 Sorghum 1 qt. 

 per 25 lbs. 

 Orleans molasses 

 2 qts. per 25 lbs. 

 Orleans molasses 

 1 qt. per 25 lbs. 

 Wet bran alone 

 Check (Unpoisoned) 



Totals 



107 



213 



188 



196 



196 



227 



131 



175 



220 



220 

 284 

 178 



97 

 192 

 126 

 129 

 145 

 168 



85 



106 



156 



183 

 234 



11 



1632 



703 



