GRASSHOPPERS AND OTHER INJURIOUS INSECTS OP 1911 AND 1912. 31 



to kill a full grown rooster. Of course, this amount could not be obtained in 

 a day's feeding upon the grain and foodstuff in the poisoned horse manure by 

 any one chicken. 



Aside from its value against grasshoppers another valuable point was 

 noted in regard to this new mixture. Flies are attracted to this and we find 

 that they are killed in great numbers by feeding upon the horse manure. In 

 the experiments with the roosters above quoted, we found over a quart of dead 

 flies on the floor of the shed after the mixture had been exposed for one day 

 and careful tests and counts convinced us that the mixture actually attracts 

 flies in considerably increased numbers. Following out the idea here presented 

 we would suggest such measures as the spraying of piles of horse manure 

 exposed at barns, etc., with a solution of eight ounces of Sodium Arsenite in 

 about twenty gallons of water, to which has been added one half pint of 

 molasses. This solution seems well adapted for spraying almost any exposed 

 filth which may serve as a harboring place for flies. We hope to follow out 

 several other experiments along this line if opportvuiity offers, since this 

 poison appears to offer much promise and can be purchased at very much 

 lower rates per pound than Paris Green or most of the better known in- 

 secticides. 



During the summer (1911) numerous farmers had reported to us that 

 they did not believe that the hopperdozers killed all of the grasshoppers; in 

 fact, many of them believed that unless the grasshoppers actually fell into the 

 trough and were thus drowned in kerosene they might revive. As soon as 

 opportunuity offered we tried a long series of tests to show the actual effect of 

 the kerosene under different conditions. As a result of these it was deter- 

 mined that the effect of the kerosene may vary somewhat when used very 

 late in the season and with certain species. Trials made with hundreds of 

 young grasshoppers of the harmful species showed that mere contact with 

 the cloth wing, wet with kerosene, resulted in death within a very few minutes 

 in every case. The same results held with crickets whether young or adult. 

 With adults of a few of the species having notably long and ample wings, the 

 results varied and while in some cases they were killed, some survived so long- 

 that it is possible that they might eventually recover. Our explanation lies in 

 the fact that the ample wings, folded fan-like, serve to draw the kerosene from 

 the surface of the body by capillarity. The action of the kerosene depends 

 upon its reaching one or more of the spiracles and it is evident that this lessen- 

 ing of the amount of kerosene by the tube-like foldings of the wings must 

 result in lessened effect. 



The conditions thus observed simply add another reason why the hopper- 

 dozer, like sodium arsenite or any other control method, must be applied in 

 early May and June to produce most effective results. There can be no doubt 

 of the effect of these several methods when used early but when the man most 

 affected will still delay, vainly hoping for the weather or Divine Providence to 

 intervene, he should not attribute the failure of his trials to the methods 

 but to his own delay. 



Various grasshoppers lightly wet with kerosene on the under side of the 

 body were affected as follows: 



Species. Helpless. Dead. 



M. femur-rubrum 5 seconds 1 minute 



M. atlanis 15 " 214 



M. bivittatus 20 " 2 



M. bivittatus 10 " 1 



M. femur-rubrum 30 " 2 



M. bivittatus 45 " 101/2 



This latter specimen is inserted to show the slower effects in long winged 

 forms. This was very noticeable in such species as Dissosteira Carolina, 

 Arphia pseudonietana, etc. 



In connection with our spraying experiments it may be well to 

 include here Mr. Howard's observation in 1912, showing features to 



