BUNT, OR STINKING SMUT, OF WHEAT. 3 
The Palouse region, where most of these investigations and obser- 
vations were conducted, is extremely rolling, there being almost no 
level land. Owing to the prevailing southwest winds the hills have 
become dune shaped, with the steep slope on the east or northeast 
face, where they frequently approach an incline of 45°. These 
slopes are composed of fine drifted soil, which is protected from 
excessive evaporation and are therefore more moist and fertile than 
those facing the southwest. 
Observations showed that the percentage of bunt was usually 
higher on the northeast slopes. Owing to their steepness harvesting 
was difficult and wasteful, and a great number of bunted heads were 
left on the ground. This fact apparently conformed to the first 
explanation of soil infestation. But these same slopes were the 
natural settling places for any wind-borne dust. It was also noted 
that bunt was especially likely to be produced on the east and north 
sides of brushy fence rows, thus strongly suggesting the wind as a 
probable agent in spore distribution. The following observations 
seemed to support this view, or at least were not reconcilable with 
the idea that the infestation came entirely from the old bunt heads : 
(1) When, as occasionally happened, wheat stubble was fall plowed and sown 
at once, even though the previous crop had been bunty, the percentage 
of bunt was comparatively, and actually, low. 
(2) When wheat was spring sown, the crop was almost always practically 
bunt free, even though a bunty crop had been harvested the previous 
year. 
(3) During the threshing season of a bunty year one might stand on a hill 
and see clouds of black dust rising from every threshing machine in 
sight and drifting off with the wind. 
In 1911 A. M. Richardson, then of Washington State College, 
presented evidence in an unpublished paper showing that in some 
cases bunt infestation had obtained from wind-borne spores. Further 
evidence of the same nature was furnished in the earlier controlled 
experiments in seed treatment on the college farm at Pullman. It 
was found that unless the sowing was done in late fall or late spring 
any and all treatments failed to give perfect control, even when sown 
on ground that had not produced wheat for many years. In the fall 
of 1913 arrangements were made with two farmers near Pullman to 
replow a part of their summer-fallowed fields just before seeding. 
In one instance the unplowed part produced in the following harvest 
25 per cent of bunt and the replowed part but 3 per cent. The 
unplowed portion of the other field produced 7 per cent of bunt 
against 1 per cent in the replowed part. In the fall of 1915 a series 
of periodic sowings was made on land on which wheat, so far as 
could be learned, had never been grown. In fact, there was no 
possibility that this soil could become infested except by wind- 
borne spores. The location, a cove on a northeast slope, was a 
natural assembling ground for any wind-borne material. The 
soil was prepared for seeding in July, and the first sowing was made 
on July 31. After this the soil was undisturbed except for making 
subsequent sowings. The seed was threshed by hand from hand- 
picked heads taken from bunt-free plats and was treated by soaking 
20 minutes in a solution of 1 pound of copper sulphate to 1 gallon 
of water. Sowings were made in two plats. The results are shown 
in Table 1. As no bunt appeared in sowings made prior to Septem- 
ber 2, the results of the earlier sowings are omitted. 
