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AJV ECONOMIC ENTOMOLOGY. 



CHAPTER V. 



MACHINERY. 



Having determined the character of an injurious insect and 

 the remedy to be applied, it remains to decide the method in 

 which the appHcation is to be made, — i.e., whether the poison is 

 to be used dry or in a watery mixture ; and this necessitates 

 some information concerning pumps, nozzles, bellows, and the 

 like. There is no better indication of the progress of economic 

 entomology than the large number of firms now engaged in 

 manufacturing and supplying machinery for the appHcation of 

 insecticides. Every agricultural journal contains advertisements 

 of such firms, and almost all of them issue illustrated catalogues 

 describing their wares. It will be for the farmer, with the knowl- 

 edge of his own requirements and necessities, to decide just what 

 kind of an outfit he needs, and all that can be done here is to 

 give a few suggestions as to the principles underlying the appli- 

 cation of insecticides. 



Whether we apply dry powders or watery mixtures, the prime 

 essential in all cases is thoroughness. Where poisons are to 

 kill by contact, it is easily realized that contact is essential,— that 

 is to say, that the insect must be actually touched by the poison 

 to be at all effective. I have shown that such poisons kill in most 

 instances by either entering the body through the spiracles or 

 clogging them ; hence, also, the entire insect must be covered 

 by the poison, if it is to be entirely effective. Where stomach 

 poisons are to be used, it is equally essential that all parts of the 

 plant be covered, so that, no matter how little the insect eats, it 

 will yet obtain a poisonous dose. The amount of actual poison 

 required to kill most insects is very small, but in order that they 

 may obtain even this small quantity, the entire food-plant must 

 be covered. The essential feature of a perfect machine for ap- 

 plying insecticides is, therefore, that it shall quickly, thor- 

 oughly, and economically distribute whatever poison is used. 

 In some cases the application of dry poisons is desirable, though 

 the method is often a wasteful one, besides involving a greater 



