HEAT CAIfKER OF FLAX. 
Table 2 shows that under three different conditions of shade more 
canker occurred on the heavy dark soil than on the same type of 
soil which had been covered with yellow sand a quarter of an inch 
in depth. It also shows that canker occurred most abundantly 
where the soil was shaded the least. This holds true in general 
both where sand was applied and where it was not used. 
As already stated, no canker occurred on the later sowings in 
plats B and D, and only a limited occurrence was noted in plat C, 
sown on June 27, where the canvas shades were placed, as shown in 
Figure 1. The data obtained from this plat, taken when the plants 
were about 4 inches high, are summarized in Table 3. 
Table 3. — Number of flax plants cankered under various conditions in plat C\ at Fargo. 
N. Dak., sown on June 27, 1919. 
[Data on the occurrence 
of heat canker of flax recorded on July 18, 1919.] 
Row. 
Shaded by canvas. 
Not shaded. 
Row. 
Shaded bv grain. 
On sand. 
No sand. 
On sand. 
No sand. 
On sand. No sand. 
No. 1 
■ 


1 

2 
2 




3 
4 
23 
2 
10 
3 
2 


1 
No. 11 
a 
No.2 

» 
; Xo. 12 
! 
No.3 
Xo. 13 
1 Xo. 14 
' Xo. 15 
Xo. 16 
No. 17 
No. 18 
oooooo 

No. 4 1. . . 

No.o 

No. 6 
No.7 
No. 8 



No 9 
No. 10 
1 
It is evident from Table 3 that flax plants grown behind the 
canvas shades were not cankered, while some plants were cankered 
in the same rows when not shaded by the canvas, especially where 
sand was not applied. Xo flax was cankered where nurse crops 
were used. The row havuig the most cankered plants (Xo. 3) was 
the one sown thinly (at half rate) and double spaced from the next 
row on the south. While less canker occurred in this experiment, 
the results are in line with those obtained from plat A, pnesented 
in Table 2, in that the flax was cankered most where the soil was 
shaded least and where no sand was applied. 
Experiments similar to those of 1919 were conducted during 1920, 
except that sand was omitted. A single variety resistant to flax 
wilt was used, and more variation was made in the rates of seeding. 
Six experimental plats were sown during the season at intervals of 
approximately two weeks. Canker appeared to a greater or less 
degree in the last four sowings. Plants emerging on May 28 or 
earlier were not cankered. The injury of plants in the plats where 
canker appeared occurred from 4 to 14 days after emergence. The 
data presented in Tables 4, 5, and 6 were obtained from the two 
plats in which cankered plants appeared in the greatest numbers. 
