IOWA ACADEMY OF SCIENCE 
23 
Less than fifty years ago I was rapping potato vines over a tin pan to 
catch the potato beetles that were devastating the potato fields in. Iowa. In 
fact, as far as I recall, this was my first entry into the field of economic 
entomology and I believe about my first financial income was derived from 
this sort of service. But it was a good many years afterward that methods 
of control for that pest based on knowledge of habits, life history, and chemical 
poisons were an accomplished fact in economic entomology. 
The warfare with the Rocky Mountain grasshopper, the cotton worm, the 
San Jose scale, the gipsy moth, browntail moth, cotton boll weevil, and such 
old-time pests as the codling moth, chinch bugs, and Hessian fly and others 
have either been fought and more or less completely won within the last 
quarter century or so nearly within it as to form a part of its history. 
One of the very striking lines of progress has been in the transportation 
of the parasitic enemies of injurious insects, a phase of economic work which 
had only just begun twenty-five years ago, and which has been practically 
developed within the last decade with special reference to the depredations of 
the gipsy moth and the browntail moth. While this mode of contest with 
injurious insects, especially those which are introduced is not as yet entirely 
past the experimental stage, so much encouragement has been derived from 
recent results that we must certainly look upon it as a very important phase 
of entomological investigation, and one from which we will almost certainly 
secure important results for certain pests. It may not be possible to duplicate 
in any case the phenomenal success attained in the control of the cottony- 
cushion scale in California, but the success with that species and the less 
perfect success in the case of others must at least point the way to further- 
progress, and we may expect that a certain number of important species may 
finally be controlled in this manner. 
The methods for control for introduced species the spread of which may be 
retarded by quarantine or inspection have been developed entirely within the 
quarter century and the service rendered in this manner is beyond computation. 
Now nearly every state has legislation and a national law is being inaugurated. 
To a large extent, the content and method of economic entomology have 
been appropriated in other special fields — especially is this true in horticulture, 
where the methods and results of entomological, research are appropriated to 
such degree that I doubt not many students fail to realize the incorporation. In 
medicine, also, while we still may speak of Medical Entomology, the relations 
to medical research have been so close that we may find difficulty in separating 
the doctor studying entomology from the entomologist investigating insects 
with reference to their medical aspects. The fact is that various fields have 
been opened up to a far greater extent than is possible for one man to follow 
and we have reached a stage of differentiation when to keep abreast of progress 
one must limit his effort to a limited part of the entomological field. 
But a feature of the subject which I wish especially to emphasize is the 
attitude of science, or to be more personal, the scientific worker toward the 
application of science in human affairs and for human welfare, that is, toward 
economic or applied science in all its phases. 
The time was when probably the greatest efforts in invention and in the 
application of knowledge were devoted to engines of human destruction, and 
while this effort may have been a stimulus in the acquisition of knowledge it 
