THE CONTROL OF CABBAGE BLACK-LEG. 
19 
Table VII. — Development of black-leg in cabbage seed-bed plats sown with 2- 
gram samples of treated seed at Madison, Wis., in 1919. 
- 
Length of 
exposure. 
Effect 
upon 
badly 
infected 
seeds — 
viable 
fungus 
after 
treat- 
ment 
(per 
cent) .« 
Effect 
upon slightly infected commercial seeds. 
Lot 2-18.6 
Lot 3-18. & 
Type of treatment and tempera- 
ture or concentration. 
Germi- 
nation 
(per 
cent). 
Seed- 
ling 
injury, c 
Plants 
infected 
at the 
end of 
the 
experi- 
ment 
(per 
cent). 
Germi- 
nation 
(per 
cent). 
Seed- 
ling 
injury, c 
Plants 
infected 
at the 
end of 
the 
experi- 
ment 
(per 
cent). 
75.3 
16.6 
12.0 
15.3 
12.8 
""2L7" 


92 
92 
88 
72 
81 
92 
70 
73 
46 
45 
46 
28 
32 
22 
20 
83 
81 
86 
85 
81 
67 
52 
59 
34 
11 
88 
85 
74 
55 
53 
78 
29 
30 
66 
33 
9 
O 
o 
o 
e 
e 
o 
+ 
++ 
++ 
++ 
++ 
++ 
++ 
++ 
++ 
o 
o 
o 
o 
e 
29 
16 
62 
22 
12 
5 
1 

2 
4 
2 
1 
1 
12 



1 


3 
3 
3 

3 
19 
31 
13 
----- 
i 
l 

3 
2 
3 
96 
O 
7 
Mercuric chlorid: 
Strength 1 to 1,000 
30 minutes, 
rinsed. 
'30 minutes, 
rinsed. 
30 minutes, 
unrinsed. 
1 hour, 
rinsed. 
30 minutes 
(30 minutes 
h hour 
[2 hours 
Strength 1 to 500 
Formaldehyde, not rinsed after 
treatment: 
Strength 1 to 256 
Strength 1 to 128 
Hot, 1 to 128 formaldehyde: 
At 55° C 
h minutes . 
15 minutes . 
f 1 minute . . 
At 60° C 
<2 minutes . 
(5 minutes . 
[10 minutes 
120 minutes 
]30 minutes 
11 hour 
5 minutes. 
<15 minutes 
(5 minutes. 
ilO minutes 
(15 minutes 
(12 hours... 
24 hours... 
■{48 hours... 
72 hours... 
196 hours... 
(12 hours... 
•{24 hours... 
136 hours... 
(12 hours... 
•{18 hours... 
|24 hours. . . 
........ 
20.0 
4.0 

32.6 
17.7 
36.0 
9.0 

25.0 
4.0 
4.1 
2.8 


Hot water: 
At 55°C 
At60°C 
+ 
+ 
o 
9 
Dry heat: 
AtS5°C 
92 
98 
69 
74 
78 
93 
63 
57 
79 
O 
o 
e 
e 
e 
o 
e 
6 
7 
24 
6 
At90°C 
.5 
.5 
3 
2 
At95°C 
+ 
4- 
? 
2 
h 
65 
e 

a Data summarized from Tables I to IV, lots Nos. 4-18 and 1-19. 
b Wisconsin Hollander variety, grown in 1918. 
c Symbols used: 0= No injury; ©=slight; -h=medium; +=severe; ++=very severe. 
It is evident from these trials that complete disinfection of cab- 
bage seed infected with Phoma lingam without material reduction 
in germination is not to be hoped for. It is possible that some of the 
stronger treatments may be used with certain lots of seed, but their 
recommendation for general use is out of the question. Moreover, 
it is unsafe to assume that treatment, even if carried to the point 
where reduction in germination and seedling injury begins, can 
