34 THE RICE GRASSHOPPER 



In most cases where poisonous sprays or baits have 

 been used successfully against grasshoppers, it has been 

 against the migratory forms which, at least during their 

 migrations when they are driven from their native haunts 

 by lack of food, are most omnivorous feeders, eating practi- 

 cally all vegetation in their path. It might, then, be anti- 

 cipated that they would take more kindly to poisoned bait 

 than such a comparatively dainty and specialised feeder 

 as the Rice Grasshopper. 



Notwithstanding the comparative improbability of 

 success with poisoned baits, a few experiments were tried 

 during the summer of 1910. No experiments were tried 

 with kerosene emulsion or other contact poisons as it 

 seemed clear that the expense of such a method of combat- 

 ing this pest would be much too great. 



In most of these poisoned baits, where they are success- 

 ful, the attraction to the grasshoppers lies in the sweeten- 

 ing substance — whether sugar, molasses or jaggory — that 

 is used. In our experiments, therefore, we varied the 

 strength of the jaggory more than we did that of the 

 poison as we wished, if possible, to attract the grasshoppers 

 to comparatively small quantities of bait. Spraying the 

 poison over large areas of bund was, in our opinion, out 

 of the question from a practical standpoint. 



The following mixtures and solutions were prepared 

 and experimented with both in the field and in breed- 

 ing cages : — 



A. 1 lb. lead arsenate, 5 lbs. of jaggory to 100 gallons of water 



(this is the mixture found by Lefroy to give the best results 

 in the case of the Bombay locust). 



B. 1 lb. lead arsenate, 5 lbs. jaggory to 50 gallons water. 



C. 1 lb. lead arsenate, 10 lbs. jaggory to 50 gallons water. 



D. 1 lb. lead arsenate, 20 lbs. jaggory to 10 gallons water. 



E. i lb. white arsenic, 2 oz. caustic soda and 20 lbs. jaggory to 



50 gallons water. 



F. 1 lb. white arsenic, 4 oz. caustic soda and 20 lbs. jaggory to 



50 gallons water. 



1. Experiments ivith baits in the field. 



Clumps of grass were removed with the earth, sprayed 

 with the various solutions (six clumps to each solution), 

 and spread along badly-infested bunds. These were left 

 for three days and were inspected each morning and 

 evening. In no case, however, did the hoppers show any 



