12 
BULLETIX 934. IT. S. DEPARTMENT OF AGRICULTURE. 
Table I. — Relative importance of losses by flam ping -off before and after conifer 
seedlings emergt from tin: soil. 
Series. 
Basis. 
Loss in control plats. 
Nursery and species. 
Disinfectant. 
Number of 
plats. 
Emerged 
(viable see . 
Ratio 
of 
col. 6 
to 
col. 7. 
a 
Treat- Cor- 
ed, trols. 
Be- 
fore. 
After. Total. 
Bessey (Nebraska sand hills : 
" ius banksiana 
ponderosa 
is resinosa 
1 ranlR" City southwestern 
Kafsas : 
Pinus austriaca 
Average of 9 Sulphuric acid (a) 
Average of 2 do ( 
Average of 3 do 
Pinus banksiana . 
Pinus ponderosa. 
Average of 2.. 
....do 
Average of 7. . . 
Cass Lake northern Minne- 
sota : 
Pinus resinosa. 
East Tawas 'Michigan : 
Pinus resinosa 
No. 1051 
No. 1052 
No. 1053 
No. 1054 
Nos. 1057 and 
1061. 
Fort Bayard >»ew Mexico 
Pinus ponderosa 
/1073 
\1074 
!Nos. 791 and 
792. 
Nos. 891 and 
892. 
Copper sul- 
phate. 
Zinc chlorid... 
Copper sul- 
phate. 
Formaldehyde 
do '.... 
Zinc chlorid. . . 
do 
Heat. 
Formaldehyde 
Sulphuric acid 
Formaldehyde 7 
Sulphuric acid 8 
P.ct. P.ct. 
27.2 
27.3 
54. 1 
27.5 
5 
7 
37. S 
2S. 1 
29.4 
3 
69.0- 
- 
29 
80.7 
15.3 
3 
3 
4 
3 
2 
3.8 
-'. 7 
5. 7 
7.4 
4.9 
3 
7 
5.9 
58 - 
S 
12.6 
6 
14.5 
P.ct. 
65.0 
55.4 
•83.5 
cl.39 
L03 
.54 
2.52 
12. 92. 7 
30. 9 46. 2 
37.2 
36.2 
26.2 
43.6 
16.9 
41.0 
61.9 
31.9 
5.1 
_:. - 
45.3 
18.0 
5L2 
76.2 
36.1 
48.7 
33.1 
.10 
.71 
.22 
.18 
.29 
.13 
3.25 
.35 
a Area counted, 122 square feet. b Area counted, 78 square feet, 
cln Pinus banksiana av the Bessey Nursery, the loss after emergence is slightly low and the ratio slightly 
high, because of the closing of counts on a few of the series before dam ping-off was entirely over. 
The procedure was to average the number of seedlings which 
emerged in the control plats in each series and subtract this number 
from the average number emerging (that is. appearing above the 
soil surface) in the treated plats in the same series. The treated 
plats chosen were the ones which allowed the averaging of the 
greatest number of plats treated with the same disinfectant. Only 
those plats were taken in which there was no evidence of injury to 
the seed or seedlings by the disinfectant and in which the amount 
of normal damping-ofT during the first few days after emergence 
was so slight as to indicate satisfactory initial control of the parasites 
by the treatment. In such plats it was assumed that the germination 
loss was unimportant, and the average number of seedlings appear- 
ing on them was taken as representing the number of viable seeds per 
plat. The difference between this emergence figure and the average 
emergence in the controls was taken as indicating the extent of para- 
sitic loss before the seedlings appeared, including any destruction 
of dormant seed by parasites which may have occurred as well as 
the killing of germinating seed. 
Both this ficrure and the number 
