68 HATCH EXPERIMENT STATION. [Jan. 



of the summer. While of no great economic or practical 

 importance, these attacks have been so marked and their 

 effects so conspicuous that a brief description of the nature 

 of the trouble may be of interest. The following diseases 

 were generally prevalent wherever the host trees occurred, 

 over the considerable portion of New England which we vis- 

 ited during the summer. 



A Leaf Blight of the Sycamore or Buttonwood. 



(Olocosjwrium nervisequum Fckl. Sacc.) 



Numerous inquiries reached us during the spring and 

 early summer concerning the very prevalent and destructive 

 blighting of the leaves of the sycamore tree (Blatanus occi- 

 denialis) . It is probable that every good-sized tree of this 

 species in the State was attacked by the disease. The 

 younger trees were apparently, for some unexplained reason, 

 less susceptible. The trouble appeared in May, when the 

 trees, which had just leaved out, appeared as if they had 

 been nipped by a frost or scorched by fire. The leaves with- 

 ered and turned brown, the new twigs were killed and many 

 of the leaves fell to the ground. In this condition the trees 

 lost all beauty, and became unsightly objects. This disease 

 is not entirely new in this State, although it has never been 

 so generally prevalent before. It was first described in Ger- 

 many in 1848, and has been common in various parts of 

 Europe since then. In this country it has occurred mostly 

 within the last fifteen years. It first appeared in the District 

 of Columbia, Ohio, Kentucky and other parts of the country 

 south of here, but is now widespread. 



The cause of this disease is a parasitic fungus, growing in 

 the leaves and young twigs of the tree, and causing their 

 death. Several other fungi are usually found in connection 

 with the disease, and may have something to do in causing 

 it. This disease is a very serious drain upon the vitality of 

 the tree, and often results in its death. Its occurrence early 

 in the season, however, favors the tree, since it has a chance 

 to, and in fact does, produce a new crop of foliage to carry 

 it through the season. This exhausts the tree, however, and 

 if repeated for several seasons is likely to cause its death. 



