BUNT, OB STINKING SMUT, OF WHEAT. 7 
other an Alternaria form of a species of Pleospora. This latter 
fungus begins its work very early. Its mycelium will always be 
found, both in the testa ancf in the interior among the spores, in any 
bunt head picked up in the field shortly after harvest. In most 
cases it can be isolated from standing heads before harvest. 
Table 4.— Comparative decline in the duration of the possible capacity for bunt 
infection at Pullman, Wash., as shown by successive sowings of Early Wilbur 
wheat in soil heavily inoculated on March 5 and April 4, 1915. 
Sowings in Soil Inoculated on March 5. 
Date of sowing. 
Number of plants. 
Bunt free. 
Wholly Partly 
bunted. , bunted. 
Plants in- 
fected. 
Mar. 6.. 
Mar. 8.. 
Mar. 13. 
Mar. 22. 
Mar. 26. 
Apr. 4.. 
Apr. 9.. 
Apr. 18. 
Apr. 24. 
May 5. . 
14 
14 
3 
17 
23 
44 
114 
1S3 
127 
120 
Per cent. 
78.8 
71.4 
95.0 
87.1 
77.9 
65.6 
40.9 
12.0 
2.3 
1.6 
Sowings in Soil Inoculated on April 4. 
Apr. 4.. 
Apr. 9.. 
Apr. 24. 
May 3. . 
May 8.. 
May 23. 
June 3.. 
40 
26 
14 
22 
43 
23 
51 
50 
24 
75 
11 
13 
91 
11 
24 
88 

1 
127 


50.00 
75.00 
59.20 
24.24 
27.78 
1.12 

The following facts throw some light on the longevity of the spores 
under different conditions : 
(1) Spores were germinated that had been kept dry in the Washington State 
College herbarium for 12 years. 
(2) Heads that had lain in the field from the harvest of 1911 were crushed and 
mixed with the soil in the fall of 1912 and caused an infection of more than 50 
per cent in the following crop. 
(3) In the fall of 1913 bunted heads were saved from the harvest of that year 
and stored under uniformly dry conditions. Other heads from the same plat 
were left exposed on the ground. In the spring crushed balls from these two 
lots were used in exactly the same proportion in plats sown to spring wheat. 
The average of the results from three comparative rod-row tests showed 84.4 
per cent of infected plants from indoor-stored heads and 82.4 per cent from out- 
door-exposed heads. 
(4) In October, 1914, bunt heads from the 1913 harvest were taken from the 
barn and a quantity of them buried in open ground at a depth of 8 inches. A 
portion of these heads remained undisturbed until Ma} 7 1, 1916, when they were 
dug up and mixed with soil in which 2-rod rows of spring wheat were sown. 
These rows produced 279 plants, of which 44.29 per cent were infected. The 
control was bunt free. What was originally about a half-bushel of heads was 
used in the 2-rod rows; hence, only a very small percentage of the spores needed 
to be viable in order to produce the above infection. As a matter of fact a 
microscopic examination of these spores wheD dug up showed that they were 
mostly dead. 
Saprophytic growth of Tilletia in the Palouse soils after the germina- 
tion of the spore is limited to 50 days at most and under specially 
