IOWA ACADEMY OF SCIENCE 
99 
varieties were. Ravn came to the conclusion that as a general thing, the two 
rowed barley was more resistant than the six rowed barley. But in a season, 
when the disease is wide spread and deep seated, and where there is an 
indication of a repetition the following season, other remedies must be sought. 
&. Treatment of the Seed. 
It has been noted that the seed is a source of infection. Is there then a 
remedy to prevent the spread and propagation of the disease from the mycelium 
and conidia in the seed? For the most part this question can be answered in 
the affirmative. Ravn has found that Jensen’s hot water treatment is effective 
in dealing with both H. teres and H. gramineum. This consists in placing 
the seed in cold water, which is gradually heated to a temperature between 
52-53 degrees C., and allowing the seed to remain for five minutes. The seed 
is then cooled by being placed in cold water and later dried. A short time after- 
wards the seed can be sowm. In addition Ravn has modified the above process 
slightly, and this gives better results. The plan consists in placing the seed 
in glass receptacles and in pouring over the grain sufficient water to cover. 
The grain is allowed to soak for a period of four hours at a temperature from 
10-15 degrees C. The water is then poured off, and the receptacles covered with 
glass plates, until the next day. At that time the seed is transferred to bags 
and immersed in water. The water is heated to a temperature between 52-53 
degrees C., and allowed to remain for five minutes. Afterwards the seed may 
be sown. Where this latter treatment showed no infection, the former gave 
2,3 per cent while the untreated 12.9 per cent. Hollrung" suggests that the 
seed be treated about a month or a month and a half before being sown. 
This point does not possess particular significance, as fresh infection may 
result especially when grain is placed in old bins. Professor PotteF^ in his 
«lpaper on the “Deaf Ear of Barley’’ has called attention to the experiments 
that were performed at Cambridge University. Where a 10 per cent solution 
of copper sulphate was used all traces of a production of diseased plants were 
lost sight of. But copper sulphate has its disadvantages in the fact that it 
injures the seed. In 1907 formalin was tried out. The first solution applied 
consisted of one part formaldehyde to 240 of water; while a second solution 
consisting of one part formaldehyde to 160 parts of water was also used. 
Seeds treated by the first solution showed 2.5 per cent sick plants, while in 
the latter .9 per cent. The crop harvested by the second method showed a 
better yield as well as better filled seeds. Kuhn’s* treatment w’here seeds are 
placed for 14 hours in a % per cent solution of copper sulphate, and later 
soaked in milk of lime, as well as the potassium sulphide (% per cent solution 
in water) method of Kellerman and Swingle** were both used by Ravn and 
Potter with good results. 
In taking these different seed treating remedies into consideration the 
formalin method with a strength 1 to 160-200, will be the most effective. Pro- 
fessor Potter says with reference to H. gramineum: “It would appear there- 
fore that the best remedy is to be found in ‘pickling’ of the grains by means 
of w'hich the fungus is destroyed, while the power of germination remains 
unimpaired.” 
* Report Kansas Agr. Exp. Sta. 1889. 
**Report Kansas Agr. Exp. Sta. 1890. 
