Practical Considerations. 



165 



are famishing, it is useless to try and protect plants by 

 any application whatever. Sweetened water, which was 

 supposed to be effective, certainly has no such effect on the 

 unfledged hoppers, for they,'' went for "plants which I 

 thus sprinkled even more voraciously than for those not 

 sprinkled. Lime does not deter them ; cresylic soap will 

 not keep them from eating ; and Paris green, though it 

 undoubtedly kills those which partake, is yet no protection 

 to plants, because those which go off to die somewhere 

 after partaking are continuously followed by others which 

 go through the same experience. I gave carbonic acid gas, 

 from a Babcock fire extinguisher, a thorough trial under 

 many different circumstances and conditions, but without 

 any satisfactory results. It had very little effect upon 

 them even when played upon them continuously and at 

 short distance. They often became numbed by the force 

 of the liquid but invariably rallied again. 



A mixture of kerosene and warm water, applied through 

 an atomizer or spraying machine, is, perhaps, the best pro- 

 tection, and will measurably keep the insects off when they 

 are not too numerous. 



Paris green, mixed with flour, in proportion of one part 

 of green to twenty-five or thirty parts of the dilutent, if 

 scattered on the ground, will attract quite a number of the 

 insects, which will eat thereof and die. This mixture has 

 long been known to kill the Colorado Potato-beetle. Its 

 use against the young locusts is, however, practically of 

 little avail, first on account of their numbers, secondly on 

 account of the danger incident to the use of so poisonous a 

 remedy. 



PROTECTION OF FRUIT TREES. 



The best means of protecting fruit and shade trees de- 

 serves separate consideration. Where the trunk is smooth 



