June, '21] FORD AND LARRIMER, GRASSHOPPERS AND BAITS 285 



of time after treatment with poison bran mash. Furthermore the 

 last experiment seems to indicate that it takes very Httle poisoned bran 

 mash to kill a hopper and those receiving smaller amounts die just as 

 soon and eat just as little after poisoning as those consuming larger 

 amounts. 



OBSERVATIONS ON THE ATTRACTIVENESS OF MATERIALS 

 USED IN GRASSHOPPER BAITS' 



By A. L. Ford, and W. H. Larrimer Scientific Assistants, Bureau of Entomology 



West LaFayette, Indiana 



During recent years conflicting results as regards efficiency of kill 

 seem to have been obtained from the use of various substances in grass- 

 hopper baits. Favorable results have been reported from such wide- 

 ly differing mixtures as those made without fruit flavors or syrups, 

 those in which sawdust has been substituted for wheat bran, and those 

 containing vinegar and salt as attracting agents. Many substances 

 have been suggested as attractive baits without even giving them a 

 trial. This confusion clearly shows that much work remains to be done 

 along this line, especially in those regions east of the Mississippi river 

 where, for S3me unknown reason, grasshoppers have been on the in- 

 crease for several years. 



During the summer of 1919 a serious outbreak of Melanoplus femur- 

 rubrum occurred at Lafayette, Indiana, thus furnishing an excellent 

 oportunity for either increasing or clearing up some of this confusion. 

 Accordingly, a series of experiments was planned with reference to the 

 attractiveness of materials used in grasshopper baits, always keeping 

 their availability and cheapness in mind. 



By this plan the following points were to be determined. 

 1st. The comparative attracting power of various flavors. 

 2nd The relative attracting values of various syrups. 

 3rd. The attracting values of various body materials in poison bran 

 mash. 



To obtain accurate data on these points, the most promising of the 

 various flavors, s>Tups and materials were selected from those which 

 have been reported. It was necessary to place equal amounts of the 

 mash, mixed in various ways, in the infested fields and record the num- 

 ber of hoppers attracted to them under natural field conditions. 



The next problem was to make an accurate count of the hoppers at- 

 tracted to these baits. In order to secure the count by ordinary ob- 



