DISEASES OF CULTIVATED PLANTS 641 



two or three mildews (Microsphacra erinophila penicillata and Phyl- 

 lactinia suffulta), which, however, rarely gives serious injury to 

 foliage. In Europe the beech is attacked by a rust fungus (Melamp- 

 sora Fagi) ; the leaves are also attacked by a leaf -spot species of 

 Phyllosticta. 



BIRCH. 



Anthracnose. The anthracnose fungus of birch (Gloeosporium 

 Betularium) attacks the leaves of our American birches while other 

 anthracnoses are known on the European species. Our knowledge 

 of the injury is very limited. 



Mildews. The downy mildews of beech and alder in part occur 

 upon the birches. 



Wound Fungi. Characteristic flesh fungi invade pruning or 

 other wounds in the birch and are to be guarded against as with other 

 woody growths. 



ELM. 



Bleeding. Bleeding of pruned elm trees is often annoying as 

 well as dangerous. Asphaltum covering over cut surface reduces or 

 cures the bleeding. This is successful when searing by torch pre- 

 cedes application of dressing. 



Black-Spot. The leaves of ornamental elms are attacked by 

 black spots (Dothidella ulmi and Gnomonia Ulmea) which some- 

 times injure the leaves, and by this means checks the tree. 



Other leaf diseases also occur upon the elm. One of these is a 

 leaf-spot (Phyllosticta ulmicola) which matures its spores in the 

 fallen leaves. Gathering and burning these infested leaves will 

 prove a check on this fungus. 



Powdery Mildews (Microsphaera Alni and Uncinula macro- 

 spora, more often the latter) likewise attack elm leaves. If trouble- 

 some these should be reached by applications of Bordeaux mixture, 

 making the first application when the leaves are half grown. 



Timber-rots are also known on the elm; to be guarded against 

 in wound infection of shade trees. 



Twig Disease. In portions of Ohio and in Kentucky a dying of 

 elms which are prized as shade trees has been reported. This disease 

 shows first as a loss of leaves at the ends of twigs, often at the tops 

 of trees. It is believed that changing soil conditions have much to 

 do with this disease. To the writer it would seem that the water 

 factor with this, as with many other shade trees, may prove a deter- 

 mining cause. (Ohio E. S. B. 214.) 



HEMLOCK. 



Hemlock grows freely with us and is apparently quite free from 

 foliage troubles. 



Heart-rot (Trametes pini) and Sap Rot (Fomes pinicola) are 

 reported from districts where special attention is given to the condi- 

 tions. 



HICKORY. 



Leaf-Spot. A hickory leaf-spot (Marsonia ju gland is) is quito 



funeral and leads to dying of the leaves prematurely. (Ohio E. S, 

 , 214.) 



