DISEASES OF CULTIVATED PLANTS 577 



Root-Rot. The same parasitic fungus (Fusarium roseum) 

 which attacks wheat in the form of scab and also red clover, has been 

 found killing out alfalfa at Wooster (See Ohio Bulletin 203). This 

 fungus may survive in stubble fields where wheat and oats have been 

 grown. It readily kills off the young seedlings of alfalfa and if the 

 soil is not fully prepared for alfalfa seedings, the root-rot may ex- 

 tend its work and further destroy the stand. At present nothing 

 better is known than adequate dressings of lime, preferably raw 

 limestone, for areas to be seeded, together with their proper enrich- 

 ment. At this time warning is given as to the possible seriousness 

 of this trouble in the future. While not specifically noted in America 

 another root-rot fungus somewhat known on other crops (Rhizoc- 

 tonia) has also been reported upon alfalfa from France. Another 

 root-rot fungus (Ozonium omnivorum Shear) well known upon cot- 

 ton, also attacks alfalfa in the southwest. It is believed this is not 

 known to occur in Ohio. 



Rust. Alfalfa suffers from a rust fungus (Uromyses striatus) 

 and while it may scarcely have appeared in Ohio, it is almost cer- 

 tain to do so in time. Like the similar leaf diseases of red clover, it 

 may have rather small economic interest. (Ohio E. S. B. 214.) 



BUCKWHEAT. 



Leaf-Blight. This well known plant is frequently attacked by 

 a leaf-blight fungus (Ramularia rufo-maculans) which produces 

 whitened areas on the under leaf surfaces and causes dying of these 

 leaves. It is not known to be sufficiently destructive to warrant 

 treatment for prevention. Another leaf trouble referred to a fungus 

 (Fusicladium fagopyri) is reported from Europe, but is not known 

 in this country. 



CLOVER. 



Anthracnose. Three anthracnoses occur upon clover; the more 

 common of which is due to the same fungus (Colletotriehum trifolii) 

 as the anthracnose of alfalfa. In 1907 it attacked the clover over 

 the southern one-third to one-half of Ohio, causing dying of the 

 plants attacked. These show lesions of the stems and leaf stalks and 

 may be detected in the new seedings in late summer through the 

 dying of the leaves of these plants. It is not known how serious this 

 may prove upon clover, nor is this one known in northern Ohio. 



The second anthracnose fungus (Gloeosporium trifolii) has 

 been known longer than the first and occasionally shows by killing 

 the tops of large clover stems in meadows. It is apparently not a 

 serious disease, although a very interesting one to study in connec- 

 tion with the anthracnoses due to Colletotriehum. 



The third anthracnose upon clover (Colletotriehum cereale) is 

 the anthracnose of wheat, rye and oats. It was found to a limited 

 extent attacking clover upon the Ohio station grounds in 1909. Ex- 

 cept in microscopic characters this anthracnose cannot be distin- 

 guished from that of Bain and Essary first mentioned above. In 

 the microscopic characters the two are clearly distinguishable. It is 

 quite probable that this fungus will be found over much of the state. 



