TasBLe VI.—Destruction of fly larve in horse manure. 
DESTRUCTION OF FLY LARVA IN HORSE MANURE. 
cage experiments, Arlington, Va., 1914. 
15 
Results with ground hellebore, 
Water extract. 
Number 
of bac- Iban 
teria per Alkalin- 
Treatment of 8bushels | pyjag pales 1 gram | Manure, | ity, N/20 Nias 
Series. of manure, using 10 asin d icidal | Manure, total HCl per | Water- NH 
gallons of liquid. St cas Mes ; ealcu- | nitrogen. | 100c.c¢. | soluble F ae, 
CEU lated to (5 grams | nitrogen. | 1 othod 
dry of 5 
weight. manure). 
A | Hellebore (ground), 1 Per cent Per cent | Per cent 
pound to 10 gallons 1 of control of total of total 
82 per cent H2SO4, un- | Number. | average. | Millions. | Per cent. Cc. nitrogen. | nitrogen. 
diluted....-. oan 94 423 0. 526 7.15 27.76 2.85 
B | Same as foregoing, di- 
luted one-fifth......- 33 78 576 . 688 10. 25 24, 42 2. 76 
A | Control (water only) - QD aide ohana 506 . 695 11. 25 28. 20 1. 87 
sfB BIE) OS a SN ane: Bee aeea eae 498 . 618 15. 40 27.18 2. 59 
C 1D ee Ae ae AU ISR AE STU a HI Se LL AU a ae SO a elect eae SER 
Control average...-..-- ADSI eh tbe ell eons eee eee |MSacy ae se a ctl [arcdet a rane I erage 0 | ee one ne 
A | Hellebore (ground), i 
pound to 10 gallons 1 
92 per cent H2SOz, un- 
dilutede sees 35 SOP Rees . 456 7. 50 27.19 2. 63 
B | Same as foregoing, di- 
luted one-third...... 18 94.3 236 . 470 6.15 23. 83 3. 40 
A | Control (water only). . ih Seadousos- 29.8 . 863 9. 15 29. 32 1.85 
935 B DOS see eee fs BBY lggoocoesee 12 1, 45 13. 25 43. 72 3.25 
C DOs oss esac CY Ad ee oe ters 159 905 14.15 31.05 2. 87 
Control average...--.-.- UT [erate arco nil ese oc cine [tetera torepere eis, Cosine: soeenecel crsratreves et Seaver haa nim cette 
- A | Hellebore (ground), 4 
102 pound to 10 gallons 1 : 
per cent H»SO4....-- 315 OO ieee - 526 |(acid). 50 25. 67 2.85 
, e Ear 267 PAT ae tiyesanse . 498 |(acid). 50 21. 49 3. 40 
! ellebore (ground), 4 
103 pound to 10 gallons 
SWALCI ne acto cmc ne eer 58 OS ace Somes - 568 3. ie oa a BE eas oe 
B ID Ones Se see esas: 39 QO ur a eee eae . 554 6. : ; 
A | Control (water only). . ANAS OM entree 19.6 572 4,25 25. 00 2.10 
106 
B 1 DOR aS eos Has HO3 0) Pee eaesene Qik . 561 4, 65 26. 02 1.41 
Control average.....-- GOD D Mer ererteretete el inna ec gare sl esa date eye eau fac er Ries aoc casual acetone 
| 
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. Itis evident 
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