TREES AND TIMBER 443 



to dirty white in the center with black borders. Small 

 black pycnidia may be seen in the central regions of the 

 mature spots, which are from 10-14 mm. in diameter. 



Burning diseased leaves is recommended, accompanied by 

 use of Bordeaux mixture when economy allows. 



Tar spot, rhytismose (Rhytisma acerinum (Pers.) Fr.). — 

 Thick, shining, irregular black spots 1-1.5 cm. across 

 appear on the leaves in late summer and cause them to 

 fall prematurely, thus weakening the tree. Considerable 

 damage is often done to nursery stock. 



The leaves should be raked together and burned in the 

 fall. 



Leaf spot, rhytismose {Rhytisma pundatum (Pers.) Fr.). — 

 In this leaf spot the causal fungus forms several small 

 black dots upon the leaves as contrasted with the one large 

 black blotch of the tar spot. 



Anthracnose, glceosporiose {Gloeosporium apocryptum Ell. 

 & Ev.). — Nursery maples have been seriously injured by 

 this anthracnose. The tips of leaves of pruned twigs turn 

 yellow, then blacken and die as though frosted. Young leaves 

 and shoots are killed and by their death induce abnormal 

 branching, resulting in a compact " head." The disease 

 seems Hmited to young trees. 



Bordeaux mixture is advised, three or more sprayings. 



Powdery mildews. See Oak.' 



MULBERRY 



Bacteriose (Bacterium mori Boy. & Lamb.). — Upon the 

 leaf small reddish brown' spots, pellucid when moist, are 

 produced. The twigs and even entire trees are stunted and 



' Conn. Agr. Exp. Sta. Rpt. 1904, p. 319. 



