292 Proceedings of Indiana Academy of Science 



rotation, time of sowing or planting, time of harvesting, trap crops, clean 

 culture, plant stimulation and drainage. As a matter of fact, it is true, 

 as a rule, that all farm practices which are useful in preventing insect 

 trouble are good practices regardless of the insect question. Thus, 

 damage by the corn root aphis and corn root worm, two notoriously 

 serious corn pests, is prevented by rotation, i. e., by not growing corn 

 two or three successive years on the same ground — a good agronomic 

 practice. Injury by the Hessian fly is prevented by sowing wheat after 

 the flies issue and disappear, which date happens to be the best date for 

 wheat sowing regardless of the fly. Most species of wireworms inhabit 

 low, poorly drained ground and their occurrence in destructive numbers 

 may be prevented by proper drainage, pre-eminently a good farm prac- 

 tice. We could recount many examples of insect control by farm prac- 

 tices but these few examples will illustrate the importance of this 

 method of preventing insect losses. Even in lines of agriculture other 

 than general farm crops, good practices are becoming more and more 

 important in insect control. In orcharding certain farm practices play 

 an important role in the control of such insects as the curculio. The 

 animal husbandman finds it of greatest importance that he use sani- 

 tary measures and keep his animals in prime condition to best over- 

 come the numerous parasites which may infest his stock. Undoubtedly 

 farm practices are becoming more important phases of insect control 

 and we may anticipate their increasing use in years to come. 



(b) Mechanical methods, other than equipment used in applying 

 insecticides, are less frequently utilized although we have a few prom- 

 inent examples. The control of insects by hand picking may be con- 

 sidered a mechanical means and is probably our most primitive method. 

 Our common house screens for which the people of the United States 

 expend i)erhaps $.50,000,000 each year are mechanical controls. A 

 specially built cage-like aff"air, called the grasshopper-catcher, has been 

 utilized to large advantage in many sections of the country for the 

 control of grasshoppers. Banding trees to protect them from such in- 

 sects as canker worms is a familiar example. The use of barriers to 

 protect corn from the chinch bugs as they migrate from small grain 

 fields, the use of tarred felt disks to protect cabbage plants from mag- 

 gots, the various fly protectors u.sed on domestic animals, .sticky fly paper 

 and fly traps, are common examples of this method of insect control. 



Although the mechanical devices such as ai'e mentioned are ap- 

 parently simple they involve thorough investigations into the biological 

 principles and the thorough use of scientific facts. The same is true in 

 the case of the general farm practices. The application of the biological 

 and chemical controls themselves explain the scientific principles which 

 must be considered. 



(c) Control by insecticides is by far the most generally efl"ective 

 of the artificial insect controls, but it was only within the last half of 

 the nineteenth century that appreciable progress was made. This was 

 due largely to the ignorance and superstitions regarding insects which 

 prevailed. Even as late as the fifteenth and sixteenth centuries the 

 control of insects was a church problem. Literature refers to church 

 trials of insects and their excommunication from the church because of 



