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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 7 



hand, finely crushed sodium cyanide at the rate of 500 pounds per 

 acre. The pieces were approximately as large as a pea. This heavy 

 dosage was applied in order to give striking and easily recognizable 

 results. The cyanide was sown in the furrows and the sod turned on 

 top of the poison. The ploughing was quite evenly seven inches and 

 thus the poison was quite uniformly buried to this depth. All of this 

 field will be planted to corn next spring. A strip, of about one-half- 

 acre area, was left in the field for spring ploughing and an area on this 

 will be treated with cyanide at the time of ploughing. Across the 

 field, at right angles to the. ploughing and also the cyanide experiment, 

 a strip is to be treated with lime at the rate of one ton to the acre. This 

 strip will cross part of the cyanide treated area. The above experi- 

 mental plat was arranged to throw light on the following questions; 

 will sodium cyanide affect the soil chemically or physically, if so, will 

 the effect be influenced by the time of treatment and time of ploughing; 

 and will the cyanide be affected in its relation to the soil or in its rela- 

 tion to the insects by liming. Aside from the subject under discussion 

 the older remedial measure of culture will receive additional data. 



The pertinent results of this season's work may be summarized as 

 follows; first, sodium cyanide will not permanenth' injure the soil; 

 second, it cannot be applied while the crops are on the land nor immedi- 

 ately prior to seeding, and third, it will kill wireworms. 



L.^BORATORY EXPERIMENT WITH SODIUM CYANIDE— DIVISION A 



