400 Transactions. 
REMEDIAL TREATMENT. 
Owing to the economie importance of these fungi, mycologists in various 
parts of the world have carried out considerable work on their control. 
According to the methods of infection, this remedial treatment may be 
classed under the two heads—(i) Destruction of seed-borne spores by 
steeping in some fungicide ; (ii) destruction of perennating mycelium in 
seed. 
(i.) Many species are perpetuated by spores carried on the seed; these 
germinate and infect the host in the seedling stage (e.g., Ustilago Avenae, 
U. levis, U. bromivora, U. Jensenii, Tilletia levis, and T. Tritici) ; in fact, the 
majority of the species of economic importance are included in this group. 
The treatment recommended is to steep the seed in some fungicide 
which destroys the spores without materially affecting the germination of 
the seed. the many solutions tried, formalin sand copper-sulphate 
have been most widely used; unfortunately, both, though effective as 
fungicides, impair the germinating-vitality of the seed. 
Successful trials have recently been made with other fungicides, one of 
the most promising being powdered copper-carbonate, first recommended 
by Darnell-Smith (1917; 1921). For partieulars as to the methods of 
treatment, and a résumé of the effect of these three substances on the 
germination of wheat, see Neill (1923), who also gives a bibliography of 
recent experimental work in this connection. 
German chemists have since 1914 been experimenting with considerable 
success with various organic and inorganic compounds in connection with 
smut-control, excellent results being claimed for certain mercury-chlorine- 
m derivatives sold under the trade names of “ Uspulun," * i 
. (i) Other species are perpetuated by means of hibernating mycelium 
in the ovule (e.g., Ustilago striaeformis, U. Tritict). This mycelium 
Temains quiescent until the seed germinates, when it grows with the 
growing - point of the host until the formation of the inflorescence, 
minutes in hot water (53° C.), infection by Ustilago Avenae and “ U. nuda” 
was prevented. Freeman and Johnson (1909) found by experimenting 
with Jensen’s modified hot-water treatment that “ U. stilago nuda” and 
bel Tritici could be entirely held in check. Their methods are summarized 
ow :— 
For barley, soak in cold water for five hours ; follow by soaking in hot 
water at a temperature of 52°C. for fifteen minutes. For wheat, soak 
in cold water for five hours; follow by soaking in hot water at 54° С. for 
ten minutes, The seed may afterwards be stored for some time without - 
detriment. Germination is but slightly affected if the treatment is care- 
fully carried out. 
Osner (1916) has shown that the hot-water treatment is also an 
efficient controllant of Ustilago striaeformis. It could also be used for 
all the cereal smuts, but the work entailed is such that most growers prefer 
the simpler chemical steeps. 
