DESTRUCTION OF FLY LARV^ IN HORSE MANURE. 



ARSENICAL DIP. 



Arsenical dip, which is extensively used in the West and South- 

 west to kill ticks on cattle and sheep, was prepared according to the 

 directions given in U. S. Department of Agriculture Farmers' Bul- 

 letin No. 603 (Chapin, 1914). This solution was used in three cage 

 experiments, namely, full strength, and diluted 1 to 1 and 1 to 3 

 (Table I, Series 67, A, B, and C). 



Table I. — Destruction of fly larvse in horse manure. Results ivith arsenical dip, para- 

 dichlorobenzene , and pyridine; cage experiments at Arlington, Va. , 1914- 





Treatment of 8 bushels 

 of manure, using 10 

 gallons of liquid. 



Flies 

 emerged. 



Appar- 

 ent lar- 

 vicidal 

 effect. 



Number 

 of bac- 

 teria per 

 1 gram 

 manure, 

 calcu- 

 lated to 



dry 

 weight. 



Manure, 



total 

 nitrogen. 



Water extract. ' 



Series. 



Alkalin- 

 ity. N/20 

 HCl per 

 100 c. c. 

 (5 grams 



of 

 manure). 



Water- 

 soluble 

 nitrogen. 



N as 



NH 3 , 



Folin 



method. 



67{B 



Arsenical dip (strong) . 



Arsenical dip ( 1-1 ) 



Arsenical dip (1-3) 



Control (water only) . . 

 do 



Number. 



67 



57 



131 



826 



382 



275 



494 



37 



135 



53 



252 



96 



134 



3 



2 



4,489 



1,936 



3,212 



10 

 70 



11 



68 

 157 

 687 



77 

 307 



Per cent 

 of control 

 average. 



87 



89 



74 



Millions. 

 1,648 

 1,944 

 2,459 

 1,636 

 1,043 

 843 



Per cent. 

 0.421 

 .337 

 .547 

 .625 

 .463 

 .337 



C.c. 

 10.50 

 5.75 

 6.50 

 6.40 

 8.75 

 8.40 



Per cent 

 of total 



nitrogen. 

 33.63 

 29.97 

 33.82 

 27.84 

 41.25 

 26.70 



Per cent 



of total 



nitrogen. 



3.5 



4.4 



3.7 



7WB 





7.1 



^c 



do 





4 7 





Control average 



Pyridine, 1-100 



Pyridine, 1-500 



Control (water only) . . 

 do 







?8{b 

 (A 



63 

 



634 



798 



1,035 



1,282 



.540 

 .540 

 .611 

 .639 



8.90 

 8.65 

 9.90 

 11.15 



31.11 

 31.11 

 26.68 

 36.93 



3.0 



3.7 

 1.9 



81-j B 





2 4 



to 



do 









Control average 



Pyridine, 1-100 



do 















104 {b 



99+ 

 99+ 



209 

 128 

 19.6 



27.1 



.470 

 .449 

 .572 

 .561 



4.75 

 4.50 

 4.25 

 4.65 



28.72 

 33.85 

 25.00 

 26.02 



7.02 

 2 45 



106 {b 



Control (water only) . . 

 do 



2.10 





1 41 





Control average 



Para-dichlorobenzene, 

 h pound to 10 gal- 







79{ 



93 

 50 



97 

 78 



905 

 502 



.793 

 .505 



13.15 

 11.65 



36.07 

 35.44 



4 8 



IB 



do 



4 6 



r 



(For control see 81, A, 

 B, and C, above.) 



Para-dichlorobenzene, 

 1 pound to 10 gal- 

 lons water 





IB 



do 













f A 



Control (water only) . . 

 do 



283 

 165 



157 



.898 

 .653 

 .533 



11.40 

 10.75 

 8.15 



25.61 

 24.19 

 27.39 



2 34 



99-^ B 





4 13 



lc 



do 





2 44 





Control average 





















The two stronger concentrations killed about 88 per cent of the 

 maggots and the 1-3 solution about 75 per cent. The weaker 

 strengths apparently exerted a slight stimulating action on the 

 bacteria, and the full-strength dip showed no bactericidal action in 

 this one test. The chemical data showed no marked differences except 

 for the inoreased alkalinity where the dip was applied in full strength, 

 and this, no doubt, was due to the sodium carbonate in the dip. 



