2 BULLETIN 1120, U. S. DEPARTMENT OF AGRICULTURE. 
western North Dakota and eastern Montana, arrangements were 
made with the United States Department of Agriculture to continue 
the flax-canker investigations as a cooperative project. This paper 
deals with the results obtained under this cooperation, which began 
in 1916. 
Flax canker is a term which has been applied to any injury to 
flax which causes it to break over at or near the soil line. However, 
the symptoms are not always identical in different districts or in 
different years. Explanations of all these symptoms have not been 
obtained. 
ANTHRACNOSE CANKER. 
f 
Anthracnose canker was described by Bolley in 1910 (4 and 5), 
when he assigned CoUetotridium lini as the cause. Schoevers, in 
Holland (19), dealt with the same disease and fungus in 1915. 
Pethybridge and Lafferty {lo and 16) identified this disease in Ire- 
land, and in 1918 they named the causative organism Colletotrichum 
linicolum. They stated that the priority of Colletotrichum lini Bolley 
was not recognized because of inadequate description. T. Hemmi 
in 1920 (9) described this disease in Japan and stated that a species 
of Colletotrichum was isolated which when used to inoculate young 
plants produced a seedling blight with typical anthracnose lesions. 
In 1916 a species of Colletotrichum was isolated from flax seed of 
a number of varieties growTi at Mandan, N. Dak., in 1915. In 
inoculation experiments it proved to be parasitic on flax seedlings 
and produced what properly could be called a damping-off seedling 
disease (PI. I). 
Surveys of the seed-flax area, extending over a period of six years, 
gave evidence that different types of flax canker are widespread and 
capable of producing economic loss and in isolated cases are capable 
of destroying whole fields of flax. Strange to sa}", during these six 
years anthracnose canker was not found by the writers in the seed- 
flax area, with one exception, when it was discovered on young flax 
about an inch and a half high at Grassrange, Mont., in 1917. 
At the request of the flax-fiber specialist in the Office of Fiber- 
Plant Investigations a disease survey of the fiber-flax districts of 
Michigan and Wisconsin was made during the summer of 1920. 
Anthracnose canker was found to be widespread in the Michigan 
district. In a number of cases flax beyond the seedling stage was 
affected. In some instances as many as 60 per cent of the plants 
showed girdling, with anthracnose lesions in connection with the 
girdled areas. This condition closely resembled what Bolley de- 
scribed in 1910 and 1912 (4 and o) . I^The indications are that it is prob- 
ably a combination of injuries caused by heat and parasitic fungi. 
The area affected may be determined more by temperature and the 
resulting physiological effect on the cells than by moisture, oxygen, 
