36 THE RICE GEASSHOPPER 



Mixtures A, E and F had been quite effective. These 

 results indicate that the lioppers are fairly susceptible to 

 poison when they are compelled to eat it. The results 

 obtained in this experiment, however, when compared 

 with those of the previous two, show that it is unsafe to 

 apply the results from experiments on the effect of poison 

 in breeding-cages, to work in the field. Altogether we 

 may say that the application of arsenical poisons with a 

 view to combating the Rice Grasshopper can, on thi) side 

 of efficiency alone, not at all be recommended. This is 

 leaving out of consideration two important facts which 

 militate very much against the use of arsenical poisons in 

 the field. One of these is the heavy rainfall at this time 

 of the year which is likely to remove very much of the 

 poison from the grass and the other is the danger of poison- 

 ing cattle which might eat the grass treated. 



BAGGING OPERATIONS AGAINST THE RICE GRASSHOPPER. 



Grasshopper pests have always proved decidedly 

 difficult to combat. Their appearance over large areas 

 makes the application of stomach and contact poisons 

 costly and difficult. As already indicated, the destruction 

 of egg-masses is also commonly attended by great 

 difficulties. The result has been that mechanical con- 

 trivances for collecting these insects have been more 

 extensively used than against any other group. Many 

 such contrivances have been devised and a few of these 

 have proved very efficient in the countries in which they 

 are especially used. Among these may be mentioned the 

 so-called hopper-dozer used almost exclusively in the 

 United States on grass lands. It consists of a long 

 shallow pan on runners with a sheet of cloth or tin 

 stretched across its hinder border. In the pan is placed 

 kerosene, or tar. As this is drawn through the grass, the 

 grasshoppers spring up in front of it, strike against the 



