TREATMENTS OP SEED WHEAT FOR LOOSE SMUT 5 
SMUT CONTROL 
Untreated and treated wheat from six of the seed lots used in the 
germination test was employed in an experiment to determine the 
effects of the different single-bath treatments in controlling loose 
smut. On September 15, 1920, untreated seed and seed from each 
treatment of each of the six lots was sown in rod rows at the rate of 
6 pecks per acre. The entire series of rod rows was sown in triplicate. 
In May, 1921, smutted heads were counted. The results are pre- 
sented in Table 2. A zero in the table indicates that no smut was 
found in a complete examination of all heads in all three rows. The 
number of heads per row usually ran from 400 to 500. When less than 
1 per cent of smut was present it is shown as T (trace), and the 
total number of smutted heads found in examining all three of the 
rows appears in parentheses. Other data represent the average 
percentages of loose smut determined by making a count of 200 heads 
in each of the three rows in a set. 
Table 2. — Percentages of loose smut in six lots of Goens wheat grown from seed un- 
treated or treated with hot water, as specified, and sown in the field at Arlington 
Experiment Farm on September 15, 1920 
[T= trace (less than 1 per cent). 
The figures in parentheses show the number of smutted heads found in 
all three of the triplicated rows] 
Treatment of the seet 
Percentage of loose smut 
Kind and temperature 
Duration 
Lot 1 
Lot 2 
Lot 4 
Lot 6 
Lot 11 
Lot 14 
Hours 
Min- 
utes 
Untreated . 
5 




2 


4 
1 

5 
3 

8 

T(2) 


2 


4 
2 

8 
4 
1 
12 

2 


5 


9 
4 
T(l) 
12 
7 
T(2) 
9 

1 


5 
T(l) 

6 
2 
O 
8 
2 

2 




T(4) ' 


1 


T(l) 

7 
Modified method .... 

Single-bath method: 
At 48° C 
I ! 
{ \ 
1-7 
{ 
30 
~"~30~ 
~~"30~ 
~~~45~ 
--- 
30 
45 
T(4) 

At49° C 

3 
T(l) 

4 
2 
At50° C 
At 51° C 

6 
9 
1 1 
1 
Table 2 shows that by the single-bath method complete smut con- 
trol was obtained by soaking the seed at 48° C. for 2 hours and for 
2 hours and 30 minutes, and at 49° C. for 2 hours. Only very slight 
traces of smut were found when the seed was soaked at 49° C. for 
1 hour and 30 minutes, and at 50° C. for 1 hour and 15 minutes. 
The summary of results obtained in 1920-21 indicates that the 
single-bath method can be used successfully to control loose smut 
with less injury to the seed than is caused by the modified hot-water 
treatment, as noted by Humphrey and Potter (6). At 4S° C. the 
optimum duration of treatment for the control of smut without seed 
injury evidently lies between 1 hour and 30 minutes and 2 hours, 
and at 49° C. it is slightly above 1 hour and 30 minutes. At tempera- 
tees above 49° C. germination was considerably reduced, even when 
the seed was not soaked for a sufficient length of time to control the 
smut completely. 
