THE WAR ON INSECTS 273 



cible oils and lime and sulphur combinations are made 

 and shipped in car-load lots, while arsenate of lead, 

 absolutely unknown as an insecticide in 1888, is sold in 

 ton lots to individual purchasers. 



This development in the face of at least passive 

 opposition could not have taken place in so short a 

 time as twenty years had it not been promptly dem- 

 onstrated that the fight was a paying one. And when 

 the reader who remembers the fruit markets of that 

 earlier period, compares them with the magnificent 

 productions in our markets at present, he will realize 

 the advance that has been made. Farming and fruit 

 growing has been developed as a science, along scien- 

 tific lines. The soil is a chemical laboratory, with 

 elements ready to be combined into organic compounds 

 under proper conditions. The plants produced in this 

 soil and from these elements serve naturally as food 

 for man and other animals, including insects. Man 

 wishes to get it all for his own use and, of course, 

 therefore desires to eliminate the insects as partners. 

 Can he do it, and if so, how? 



To the first part of the question we answer yes, to a 

 very great extent; to the second there is a less definite 

 answer since every group of species must be dealt with 

 according to its kind and no one application will serve 

 for all kinds of species. Often, indeed, where insecti- 

 cides cannot be used at all, we can circumvent by plant- 

 ing at proper times, rotating crops so as to prevent 

 undue increase, and by harvesting so as to destroy the 

 insects before they mature. In the garden and in the 

 greenhouse where conditions are more under our 

 control, injury from insects can be reduced to a mini- 

 mum, and the records from our orchards show that 

 wormy fruits are not necessary features in a crop. 



We have learned that as against practically all 

 18 



