18 
BULLETIN 1230, U. S. DEPARTMENT OF AGRICULTURE. 
temperatures. Spores incubated 18 days at 29.1° C. failed to germi- 
nate and when afterwards exposed several days to optimum con- 
ditions showed no sign of life. 
Inoculated wheat seedlings were later removed from the several 
incubator chambers and transplanted to a field nursery plat. All 
plants were in first leaf or older when transplanted and came to 
maturity in the field; but in no case was there any evidence of bunt 
infection, notwithstanding the fact that during the period of incu- 
bation the seedlings were in contact with the parasite in every stage 
of its saprophytic development. This would seem to afford further 
support to the tentative position taken by the writers that there is 
a possible correlation between the degree of probable infection and 
the relative soundness of the coleoptile tissue. 
It is not known how the bunt organism gains access to its host. 
Culturing the fungus on cellulose agar failed to demonstrate its 
ability to digest cellulose and there is no definite evidence of its 
dependence on enzymic agents to prepare the host tissue for invasion. 
It is not improbable that entry is made by way of moribund coleoptile 
tissue, or possibly the way may be prepared for it by the action 
upon the coleoptile of some soil organism. 
CONTROL OF BUNT. 
NURSERY STUDIES IN SEED TREATMENT. 
Experiments in seed treatment for the control of bunt were begun 
at Pullman, Wash., in the spring of 1914. Bunt spores were worked 
into the soil on April 19, and sowings in plats of three 1-rod rows 
each were made on April 24, with the results shown in the first oart 
of Table 14. 
Seed treated as shown in the second part of Table 14, dried, and 
then bunted, was sown on October 20, 1914, in soil subject to bunt 
showers. The results show the combined effect of seed-borne spores 
and soil infestation. 
Table 14. — Relation of soil infestation to infection of wheat by bunt at Pullman, 
Wash., in April and October, 1914- 
Sowings in Soil Inoculated on April 19 and in Clean Soil. 
Plat. 
Seed treatment. 
Plants 
infected. 
No. 1 
Seed treated 30 minutes in a solution of 1 pound of copper sulphate and 1 
pound of salt to 2$ gallons of water, sown in infested soil 
16.3 
No. 2.... 
4. 1 
No. 3.... 
Seed treated 2 hours in a l to 240 solution of formaldehyde, sown in Infested 
50.1 
No. 4 
Seed treated as in plat 3, then bunted, and sown in clean soil 
22. 9 
Sowings on October 20 in Soil Subject to Bunt Showers 
No. 1.... 
Seed treated 30 minutes In a solution of 1 pound copper sulphate and 1 
40.3 
No. 2 
59.7 
No. 3 
Seed treated 30 minutes in a solution of 1 pound copper sulphate in 2A 
gallons of water '.. 
to. 2 
No. t 
Same as plal •'■; washed in water after treatment 
65. 7 
No. 6 
B2. S 
No.fi 
79.2 
