FebniarA-, '15] ferxald: needs in economic entomology 



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If this be true, how much more is it true of m^any others of our most 

 common pests. How much uncertainty is to be found with reference 

 to the fall brood of the army worm — what method of spraying is the 

 best to use for the codling moth — how may we best attack the species 

 of white grub, wire worms, etc.? But it is unnecessary to multiply 

 examples. They will occur in too large numbers to all. 



First, then, let me make a plea for more exhaustive studies of the 

 life histories of even our most common pests. Some small, apparently 

 unimportant point, perhaps already partly revealed, may on investiga- 

 tion prove the key to a new and successful method of control or at least 

 solve some perplexing point. Thus the discovery of aerostatic hairs in 

 young gypsy moth larvae has provided a possible explanation for the 

 appearance of colonies in unexpected places and has pointed out the 

 necessity for close watching far bej'ond limits of continuous distribution, 

 to discover and suppress such colonies before they have become so 

 large as to make this impossible. 



After all, we have thus far been merely skimming the surface in this 

 part of our work and among other things not the least important is a 

 thorough knowledge of the lives of our insect foes. 



What has just been said also holds good for another class of insects — • 

 those which though ordinarily not injurious may at some time be- 

 come so. When the saddled prominent {Heterocampa guttivitta Walker) 

 suddenlj^ appeared in destructive abundance a few years ago, the en- 

 tomological workers in the region attacked were seriously handicapped 

 by the fact that practically no inform. ation about this insect was avail- 

 able, and their time was taken, less by giving advice what treatment 

 to use, than in finding this out for them.selves. Of course, this could 

 not have been avoided, but nevertheless careful studies of insect& 

 not ordinarily destructive may at alm.ost any time become of extreme 

 value. 



Another subject which needs much more investigation, is that of in- 

 secticides. Just as quinine was empirically known as a treatment for 

 malaria long before the cause of the disease was known, so are a num- 

 ber of insecticides used in treatment, with no definite knowlege as to 

 the nature of their action or of their effect on plants. A thorough study 

 of various materials, both am^ong stomach poisons and contact insec- 

 ticides, to determine their effect on insects, the way in which they may 

 be best applied, their action if any, on plant tissue, the range limits of 

 safety in strength for application, and variation in any of these points 

 under varying conditions of light, temperature, humidity and other 

 conditions, should be made with care if we are to learn how and when 

 to apply insecticides with entire confidence in the results. Xew stomach 

 poisons are undoubtedly awaiting discovery, yet until ^dthin the last 



