DESTRUCTION OF FLY LARVAE IN HORSE MANURE. 



15 



Table VI. — Destruction of fly larvae, in horse manure. Results with ground hellebore; 

 cage experiments, Arlington, Va., 1914- 



Series. 



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. 



Alkalin- 

 ity, N/20 

 HC1 per 

 100 c. c. 

 (5 grams 



of 

 manure). 



Water- 

 soluble 

 nitrogen. 



N as 



NH 3 , 



Folin 



method. 



92^ 



f A 



93{B 



lc 



102J 

 IB 



103J 



[b 

 106 {b 



Hellebore (ground), 1 

 pound to 10 gallons 1 

 per cent H2SO4, un- 

 diluted 



Same as foregoing, di- 

 luted one-fifth 



Control (water only) . . 



Do 



Do 



Control average 



Hellebore (ground), 1 

 pound to 10 gallons 1 

 per cent HsSO-t, un- 

 diluted 



Same as foregoing, di- 

 luted one-third 



Control (water only) . . 



Do 



Do 



Control average 



Hellebore (ground), J 

 pound to 10 gallons 1 



per cent H2SO4 



Do 



Hellebore (ground), J- 

 pound to 10 gallons 



water 



Do 



Control (water only) . . 



Do 



Control average 



Number. 

 10 



33 

 192 

 114 

 145 

 150 



35 



18 

 551 

 333 



67 

 317 



Per cent 

 of control 

 average. 

 94 



Millions. 

 423 



576 

 506 

 498 



Per cent. 

 0.526 



.688 

 .695 

 .618 



C.c. 



7.15 



10.25 

 11.25 

 15.40 



Per cent 



of total 



nitrogen. 



27.76 



24.42 

 28.20 

 27.18 



Per cent 

 of total 

 nitrogen. 

 2.85 



2.76 



. 1.87 



2.59 



94.3 



236 

 29. 

 12 



159 



.456 



.470 

 .863 

 1.45 

 .905 



7.50 



6.15 

 9.15 

 13.25 

 14.15 



27.19 



23.83 

 29.32 

 43.72 

 31.05 



2.63 



3.40 

 1.85 

 3.25 



2.87 



315 



267 



58 



39 



4,489 



1,936 



3,212 



98+ 

 99 



19.6 

 27.1 



.526 



,49S 



. 568 

 .554 



.561 



(acid). 50 

 (acid). 50 



3.50 

 6.15 

 4.25 

 4.65 



25.67 

 21.49 



22.70 

 28.34 

 25.00 

 26.02 



2.85 

 3.40 



1.32 

 2.10 

 1.41 



The water extract proved to be just as satisfactory as the acid 

 extract. Table III, series 108 and 112, shows additional results from 

 some cage experiments at New Orleans, in which the effectiveness 

 appeared to be very low, but the results are of doubtful value for 

 the same reasons pointed out on page 8. It is very difficult to 

 explain why so little larvicidal effect was found in series 112 in 

 view of the uniformly good results in other cages and open piles. 



Results from the application of water extracts of ground hellebore 

 applied to open piles are shown in Table IV, series 44 to 48, inclusive. 

 When used at the rate of one-fourth of a pound to 10 gallons, it had 

 a variable larvicidal action, never above 50 per cent. At the rate of 

 three-eighths of a pound to 10 gallons the results were, on the aver- 

 age, somewhat higher., but none was above 70 per cent; at the rate 

 of one-half pound to 10 gallons series 44, A and B, Table IV, showed 

 59 and 62 per cent action; 48, C and D, showed 44 and 62 per cent; 

 and Table V, series 43, A and B, showed 99 per cent effectiveness. 



Powdered hellebore was used in several open-pile experiments at 

 New Orleans, and the results, as shown in Tables IV and V, indicate 

 that the application of one-half pound per 10 gallons was uniformly 

 favorable, the percentages varying from 88 to 99, the average of 12 

 open-pile experiments being 95.5 per cent. With three-eighths or 

 one-fourth pound of powdered hellebore to 10 gallons the larvicidal 

 effects were lower but still showed considerable action. It is evident 



