442 



DISEASES OF ECONOMIC PLANTS 



MAPLE 



Leaf spot, phyllostictose (Phyllostida acericola C. & E.). — 

 A large proportion of the leaf maj^ become involved, 

 causing premature defoliation which materially lessens the 



Fin. 19H.^ Maple tar spot. Aftor HeaUI. 



value of the tree for ornament or shade. The silver maples 

 are especially susceptil^Ie, and their sale has thereby been 

 reduced. The leaf spot was first noted in 1874 and is dis- 

 tributed throughout the United States. The blackish, 

 subcircular spots as they enlarge change to brown and later 



