17 

 Diagram of Pi,ats in 1897. 



Results in 1897. — Comparatively few beetles came from neigh- 

 boring fields and hence the results were more satisfactory than 

 in 1896. As shown in the diagram the yield of the half acre 

 which was sprayed three times was twice that of the half acre 

 sprayed but once. 



The results of spraying alone as a means of combating the 

 beetles compared with depending entirely upon the machines 

 for catching the insects may be shown by comparing Plat I to a 

 near-by field upon which the machines alone were used. The 

 conditions were practically the same in both cases and the yield 

 was about the same but there was a decided difference in the 

 cost of treatment. In the field referred to a machine was kept 

 running a part of every day for nearly three weeks, which is not 

 exceptional, at a cost of $4.05 per acre for labor while the cost of 

 spraying, with a power sprayer covering six rows, was but $2.58 

 per acre for labor and materials for the three applications. 

 Thus the expense of spraying was but Ittle compared to the 

 yield and much less than the cost of running the machines long 

 enough to produce the same results.' 



SHOULD SPRAYING ALONE BE DEPENDED UPON IN COMBATING 



THIS INSECT? 



Although the results in the above experiments are very gratify- 

 ing in favor of spraying, in many seasons it will be found imprac- 



7 In the field referred to the machines were used but otice^a day throngh- 

 out the entire three weeks. Usually it is necessary to go over the fields 

 twice a day for a week or ten days, thus increasing the expense. 



