26 BULLETIN 1029, U. S. DEPARTMENT OF AGRICULTURE. 
utes. This occurred under weather conditions favorable to the 
disease, owing to frequent rains. 
(8) In 1919, in the same locality, under dry weather conditions, 
the disease was quite effectively controlled by seed treatment, soak- 
ing in 1 : 500 mercuric chlorid for 30 minutes, followed by rinsing 
in clean water. At Shiocton and Appleton, Wis., where longer and 
more frequent rainy periods prevailed between the appearance of 
primary centers and transplanting, serious epiphytotics developed 
from the same lots of seed as used in the Eacine district. It was 
thus shown that even this strong treatment was insufficient to con- 
trol the disease effectively when climatic conditions favored the 
rapid spread of the fungus from primary centers. 
(9) Since treatment reduces the number of primary centers and 
retards their development somewhat and since it is also a preven- 
tive against seed-borne black-rot organisms, it should be recom- 
mended. The limitations to success in the control of black-leg, how- 
ever, should be recognized. 
(10) Trials have developed the fact that different lots of cabbage 
seed may vary considerably in their relative susceptibility to injury 
from seed-disinfection treatments. Stronger treatment than a 1 : 256 
or 1 : 240 solution of formaldehyde or a 1 : 1,000 solution of mercuric 
chlorid for 30 minutes followed by rinsing is unsafe for general use. 
Of these two treatments, the mercuric chlorid seems to be slightly 
superior in eradicating the fungus. It is true, however, that many 
lots of seed will stand much more severe treatment, especially with 
mercuric chlorid, but in the event of such treatment preliminary 
tests should always be made. 
(11) In view of the limitations of treatment in controlling black- 
leg special attention should be given to securing disease-free seed. 
