LITERATURE ON BUNT OF WHEAT. 17 
spores treated 2 hours in a 0.1 per cent solution. Those treated 
-1 hour and washed gave complete germination in 14 days, while 
untreated spores gave complete germination on the fifth day. 
| Sutton and Pridham (362), Ditzell and Downing (99), Sutton and 
| Downing (361), and Soutter (348, 349) performed some experimental 
| work to determime what fungicidal treatments gave the most effec- 
tual protection against infection through reinfestation of the seed. 
| They all agree that copper sulphate gave the most satisfactory 
- results. . 
In 1918 Darnell-Smith and Ross (94) reported on three years’ experi- 
ments in the use of dry copper carbonate as a seed treatment for 
_ bunt prevention. They found it effectual as a fungicide and nonin- 
_ jurious to the seed. In fact, they believed it stimulated germination 
__and increased the yield. These conclusions have been fully confirmed 
_ im experimental results obtained by Mackie and Briggs (254). 
Stormer (357, 358) studied the relative merits of a number of 
| treating processes, in both laboratory and field, in 1909 and 1910. 
_ He asserts that a 16-hour immersion in a 0.5 per cent solution of copper 
_ sulphate kills the spores in unbroken bails. This statement is open 
to question and is not confirmed by resuits obtained by other investi- 
$ 
x 
_ gators. He failed to restore viability to spores treated with copper sul- 
_ phate by washing them with 0.5 per cent solution of hydrochloric acid. 
e Hiltner (155) and Hiltner and Gentner (161) urge the use of mer- 
_ curic chlorid as a treatment for the seed of winter grains, chiefly as 
a protection against Fusarium and other soil fungi. Their experi- 
_ mental evidence of a resultant increase in plant vigor and in the pre- 
_ vention of winterkilling is so convincing as to warrant our considera- 
_ tion of its more general adoption as a bunt preventive. 
_ Riehm (326) conducted some experiments on the lethal effect of 
_ certain synthetic dyes on Tilletia spores and found that none of them 
_ killed the spores in the unbroken ball. Spores in balls, treated 10 
_ minutes in a 1 per cent solution of Antiavit green and Antiavit blue, 
were delayed in germination. Free spores were killed by Antiavit 
blue, Antiavit green, Antiavit, Victoria blue, and acid violet, but 
_ chlorophenate of mercury, 0.05 per cent solution, killed spores in one 
z hour with negligible injury to the seed grain. 
Lehn and Vasters (237) found that the amount of spores carried 
on the seed grain was approximately proportional to the percentage 
of bunt in the resulting crep. Gentner (132) found treatment with 
_ mercuric chlorid a perfect protective against Penicillium and Fusa- 
rium, while formaldehyde promoted the attack of these fungi. He 
_ says this fungicide is much used in Denmark, Sweden, and Russia in 
_ the treatment of seed wheat and rye. 
__ Remy and Vasters (322) experimented with a alee fungicide 
_ known as Uspulun, the active principle of which is chlorophenate of 
_ mercury, which is reported to afford perfect control of bunt without 
injury to the seed when used in a strength of 0.25 per cent for an 
immersion period of one hour. 
Weck (391) records the results of experiments with Uspulun, which he 
_ carried on for three years. He found that the action of this fungicide 
as a bunt preventive was perfect, that the viability of the seed was 
unaffected, and subsequent growth of the geedling was stimulated. 
6§2675—24——3 
—- . im. 
20° to 33° C. With formaldehyde, no germination was observed in — 
LO ee 
