BUNT, OR STINKING SMUT, OF WHEAT. 5 
In 1916 a series of sowings was made under practically the same 
conditions as in 1915. The results are shown in Table 2, together 
with the collections of a spore trap located on the plat. It is worthy 
of mention that during the week of August 15-21 the nearest thresh- 
ing operations were probably 30 miles away. 
Two further experiments were made in 1915 to establish the causal 
connection of the wind-borne spores to soil infestation. 
In the first experiment a tract of ground well situated topo- 
graphically for the settling of wind-borne material was selected, 
and a plat 12 by 16.5 feet was covered with straw to a depth of 4 
to 6 inches on September 25, 1915. This covering of straw was 
burned at once to destroy by heat the spores on the soil. A similar 
adjacent area was left as a check plat. 
Three 1-rod rows were sown in the burned-over plat on September 
25 and the same number in the check plat. These sowings were 
duplicated on October 8 and November 5. From September 25 to 
October 8 there was probably an additional fall of bunt spores. 
The seed used was Hybrid 143 from hand-picked heads from a 
clean or bunt-free crop and threshed later in a clean sack. The 
seed was then treated 90 minutes in a solution of 1 pound of formal- 
dehyde to 30 gallons of water. Plant counts only were made. The 
results are given in Table 3. 
Table 3. — Results obtained by sowing bunt-free seed wheat in alternate plats of 
heat-sterilized soil at Pullman, Wash., at intervals during the period from Sep- 
tember 25 to November 5, 1915. 
Date 
sown. 
Treatment. 
Total 
plants. 
Condition of plants (per cent). 
Bunt free. 
Wholly Partly 
bunted. ! bunted. 
Sept. 25. 
/Burned 
\Unburned (check) 
188 97. 34 
134 ! 62.60 
1.06 I 1.59 
25.27 11.94 
/Burned 
221 94.11 
21 9 
3.17 t 2.72 
Oct. 8... 
"\Unburned (check) 
11.87 6.40 
100 
100 

Nov. 
\Unburned (checks .' 

There had been considerable rain prior to September 25, and it is 
possible that some spores were carried down into the soil out of 
reach of the heat. It is also almost certain that some spores fell 
between September 25 and October 8. At the same time some were 
being eliminated on the unburned control by germination and sub- 
sequent death. 
In the second experiment, 1 square rod of summer fallow adjoin- 
ing the plat used in the first experiment was turned with a spade 
on October 6. 1915, the greatest possible care being taken to bury 
the surface soil. It was estimated that 90 per cent of the surface 
soil was placed below seeding depth. This plat was sown on October 
8. A control plat immediately adjoining was sown at the same time 
in undisturbed summer, fallow. Clean seed of Hybrid 143 was used 
after treatment for 90 minutes in a 1 to 240 solution of formaldehyde. 
The sowing was made with a sterilized garden seeder, and the re- 
E lowed plat was sown first. Merely a plant count was made at 
arvest. The yield was much the best on the replowed plat, which 
