DISEASES OF CULTIVATED PLANTS 413 
OAT-GRASS 
Anthracnose. The same anthracnose fungus (Colletotrichum cereale Manns.) 
before described as attacking blue-grass, chess, oats, wheat, rye, etc., also 
occurs upon oat-grass. It is less liable to cause serious injury here than on the 
cereal grains. 
Smut. There has been at the Station a smut on tall oat-grass (Arrhena- 
therum elatius L.) which closely resembles loose smut of oats:but is, in fact, a 
separate species of smut whose mycelium survives in the rootstocks of the oat- 
grass (Ustilago perennans Rostrup.). The smut is thus continued in the same 
plants from year to year. It is not clear whether the smut would be transmitted 
in new seed, but there is some danger, at least. 
ONION 
Bacterial Disease. See heart-rot below. 
Blight. Leaf blight or scald of onions during mid-season, when the weather 
is warm and dry, is rather a common occurrence. This was especially notic- 
able during 1898 and 1899. While often attributable to insects, species of fungi, 
especially molds (Macrosporium Sarcinula parasiticum (B.) Thiim—J. Porri 
Ell.) were abundant in the seasons named. It may be possible to check these 
molds by spraying. : 
Fusarium Blight. This is often serious on young onions in old soil and is the 
forerunner of heavy losses from soft rot in storage. 
Downy Mildew (Peronospora Schlei- 
deniana D’By.) is likely to occur upon 
onions, although it has not been seen 
in Ohio by the writer. The treatment 
would be as for downy mildew of other 
plants. . 
Dry or Black Neck-Rot is the most 
serious disease of white onions in 
Ohio since the losses are so very 
large from it, particularly in Hardin 
County. The white onions are grown 
for somewhat special markets and it 
is the custom, at present, to gather 
early before the tops fall over, to top 
at once, and put up in crates in order. 
to preserve the white color of the onion. 
As arule this is not practiced with 
black, red and yellow sorts, so that 
Fig. 63. A white onion that has been destroy- 
this neck or dry-rot is not so common 
with them. Preliminary investigations 
have been made of this trouble and it 
appears to be clearly different from 
the smudge fungus which also 
disfigures the exterior of white onions. 
ed by a blackneck or dry-rot fungus, Sclerotinum 
cepivorum Berk. This parasite has entered the 
onion through the green neck which was cut off 
at the time of harvesting the crop, (From a 
photograph by T. F. Manns). 
The fungus of dry-rot or black-neck 
(Sclerotium cepivorum Berk.) requires further investigation. -(See Sorauer 
Pflanzenkrankheiten third edition, II 302-3). In Ohio onion districts the losses 
are very serious between the gathering of the white onions and time for winter 
storage while the crates are piled in buildings or in covered ricks in fields. 
