452 OHIO EXPERIMENT STATION: BULLETIN 214 
WALNUT 
Anthracnose or Leaf-Blight. The leaves of walnut, as well as the leaves of 
butternut, are attacked by an anthracnose fungus (Marsonia juglandis Sacc.) 
which in common with other anthracnoses, is’ capable of serious injury to the 
leaves of these trees. It is believed that this fungus will be held in check by 
sprays. 
Leaf-Spot. The walnut is also attacked by other leaf fungi producing leaf 
spots, but these have not been investigated by us in Ohio. 
Mildew... The same powdery mildew which attacks a variety of trees 
(Mycrosphaera alni DC.) also attacks the leaves of walnut, growing over and 
forming a mildew covering. 
WATERMELON 
With the possible exception of the wilt disease and the leaf-spots, the diseases 
of the watermelon are the same as those which attack cucumbers and musk- 
melons. They include anthracnose, downy mildew and leaf blight. The leaf-spot 
of the watermelon is referred to a distinct fungus (Cercospora citrullina Cke.) 
though its ravages are, possibly, not general. (See Bulletins 73.89, 105). In 
the treatment of watermelon vines it is advisable to use the more dilute Bordeaux 
mixture, Bordeaux II, of the calendar. 
WHEAT 
Anthracnose (Collettorichum 
cereale Manns). In 1907 centrifuge 
examinations were made by the 
Assistant Botanist showing the 
presence of anthracnose spores in 
the washings of shriveled wheat 
samples. The disease was dis- 
covered in the fields generally ov- 
er Ohio in 1908 and has recently 
been described in Bulletin 203. 
This anthracnose is certainly the 
cause of shriveling in wheat. It 
appears to be the obscure trouble 
sought for some years by the 
writer. In common with other 
anthracnoses it develops as ma- 
turity approaches and on wheat 
it attacks the lower portions of | 
the stems and sheaths resulting | 
in apparent whitening of the 
spikes with decided shriveling of 
the grain. The fungus may be 
detected by the color changes in 
the field and by the dark spots 
appearing on the sheaths and 
stems where attacked. It is be- 
lieved that thorough separation 
of shriveled grain by recleaning 
seed wheat and treatment of seed } 
wheat with formaldehyde drench [i 
will be favorable to keeping 
down the amount of anthracnose. Fig. 101. Culms of wheat with both stems and 
It is admitted that the presence sheaths attacked by anthracnose. The dark spots are 
caused by the fungus. From Bulletin 203. 
of the fungus upon grasses and 
