6 BULLETIN 408, U. S. DEPARTMENT OF AGRICULTURE. 



Table 3. — Destruction of fly larvae in horse manure — Results with fertilizer mixtures. 

 [Cage experiments, Bethesda, Md., 1915.] 



No. 



Material used. 



Treatment of 8 bushels manure with fol- 

 lowing amounts of mixtures, then 

 sprinkled with 10 gallons of water. 



Flies 

 emerged 

 (num- 

 ber). 



Apparent 

 larvicidal 

 effect (per 

 cent of 

 control 

 average). 



Flies emerged 



from control 



cages. 





Num- 

 ber. 



Aver- 

 age. 





Calcium cyanamid+ 

 acid phosphate. 



do 



A, 1 pound calcium cyanamid+4 

 pounds acid phosphate. 



B, 2 pounds calcium cyanamid+ 2 

 pounds acid phosphate. 



C, 11 pounds calcium cyanamid+ 2\ 

 pounds acid phosphate. 



A, f pound calcium cyanamid+ 6 

 pounds acid phosphate. 



B, f pound calcium cyanamid+ 6 

 pounds acid phosphate. 



A, 2 pounds saltpeter-!- 2 pounds acid 

 phosphate. 



B, 2 pounds saltpeter + 2 pounds acid 

 phosphate. 



A, 1 pound calcium cyanamid+ 2 

 pounds gypsum. 



B, 1 pound calcium cyanamid+2 

 pounds gypsum. 



(A, 4 pound'borax+0.3 pound gypsum. . 

 \B, f pound borax+0.3 pound gypsum.. 



156 



16 



89 



905 



831 



1.934 



1,661 



610 



385 



37 

 22 



90.5 



99.0 



94.0 



67.5 



70.2 



30.6 



42.5 



78.2 



86.3 



98.7 

 99.0 







1 

 2 



1,075 



1,872 



2,910 



2,665 



2, 910 



2,665 



2,910 



2,665 



2,910 

 2,665 



| 1,474 

 \ 2,787 



3 



4 

 5 



Chile saltpeter+ 

 acid phosphate. 



Calcium cyanamid+ 

 gypsum. 



Borax + gypsum 



J 



| 2,787 



1 2,787 

 } 2,787 



Calcium Cyanamid (CaCN 2 ) and Gy«psum (CaS0 4 ). 



A mixture of 1 pound of calcium cyanamid and 2 pounds of gypsum 

 was used in duplicate in cage experiments at Bethesda, Md., with an 

 average larvicidal action of 82 per cent (Table 3, No. 4). This is very 

 nearly as high as the average larvicidal action for mixtures of 1 pound 

 of calcium cyanamid with varying amounts of acid phosphate, and in- 

 dicates that gypsum may be used in place of acid phosphate in mix- 

 tures with calcium cyanamid. 



Borax (Na 2 B 4 7 ) and Gypsum (CaS0 4 ). 



Although borax is not a fertilizer, it was tried in a mixture with 

 gypsum with the idea that the S0 4 radical in gypsum might tend to 

 reduce the toxic action on plant growth, which is known to result 

 from the application of large amounts of borax. The figures given 

 in Table 3, No. 5, show that borax gave excellent larvicidal results 

 in the presence of gypsum, but the effect of manure treated with this 

 mixture on plant growth was not determined. 



Calcium Cyanamid, Kainit (KC1 and MgS0 4 ), and Aero Phosphate. 



This is an ideal mixture from the point of view of a fertilizer, as it 

 furnishes the three essential elements of plant food, namely, nitrogen, 

 potash, and phosphoric acid. 



The results of 8 open-pile experiments, using from one-eighth pound 

 to 1 pound of calcium cyanamid in the mixtures, are recorded in 

 Table 4, Nos. 2 and 3. The larvicidal results were all low and 

 irregular, varying from 10 to 81 per cent. 



