INJURY BY DISINFECTANTS TO SEEDS AND ROOTS. 
23 
. 
days later resulted in preventing most weed growth, but not all. 
Ammonia alone, 0.5 ounce per square foot, had no effect on the weed 
stand 65 days after application. 
TESTS OF MISCELLANEOUS DISINFECTANTS. 
Tests were also made with disinfectants other than sulphuric 
acid. These are summarized in Table VI, together with enough 
sulphuric-acid tests to afford a basis for comparison. Because a plat 
can be directly compared only with the others sown at the same time, 
the plats are grouped by series rather than by disinfectants. 
Table VI. — Injury to pines and weeds by miscellaneous disinfectants. 
Plat. 
Disinfectant. 
Substance 
used. 
Per square 
foot. 
Ounces, 
Solu- 
tion. 
Days from 
treatment 
to- 
Sow- 
ing. 
Weed 
exami- 
nation. 
Injury to pines. 
Weeds present in 
plats. 
Plnus divaricata: 1 
62 
64 
P. ponderosa: 1 
4152 
416 2 
P. divaricata: 1 
Series 501 (8 
checks). 
P. ponderosa: * 
Series 504 (5 
checks). 
{Copper carbo- 
nate (basic). 
Ammonia 
Sulphuric acid 
do 
Formalin. 
....do. 
None. 
H y drochloric 
acid. 
Nitric acid 
Sulphuric acid 
do 
....do 
....do. 
None . . 
Formalin *. . 
Sulphuric acid 
.do. 
0.017 
.275 
172 
257 
Pints, 
1.4 
1.4 
1.4 
Germination re- 
duced to less 
than one-sixth 
of that in checks. 
Nearly all seed- 
lings which 
came up were 
severely injured. 
Injury not serious. 
.... do 
125 
125 
Germination re- 
duced to less 
than one -quar- 
ter that on other 
plats. No death 
due to disinfect- 
ant after germi- 
nation. 
None. 
,375 
,125 
,141 
,188 
,25 
2 
1.5 
2 
30-31.. 
30-31.. 
30-31.. 
30-31.. 
30-31.. 
30-31.. 
None. 
Slight or none. 
Slight 
Moderate to heavy. 
Moderate 
Very heavy . 
562 
2*1 
None. 
. do . 
.do. 
Portulaca and 
grass abundant; 3 
A maranthus re- 
troflexus common. 
One - half or two- 
thirds as many as 
in checks. 
Grass rare; Portu- 
laca, 2 or 3 plants. 
None. 
Do. 
A single trifoliate 
legume. 
None. 
Mollugo, grass, and 
Portulaca abund- 
ant; Amaran- 
thus and Euphor- 
bia frequent. 
Half as many as in 
checks, mainly 
grass. 
Grass/at edge only; 
Equisetum, 2 
plants. 
Grass, 2 plants. 
1 Watering as in ordinary nursery practice. 
2 Germination exceptionally rapid. 
3 "Abundant" indicates usually 100 or more plants per plat; "frequent" indicates 20 or more ;" common" 
indicates intermediate numbers. All plats measured 2 by 4 feet. 
4 Watering very frequent. 
5 Plats covered tightly for 3 days after treatment to prevent too early evaporation. 
