PEAR DISEASES 347 



the fungus commonly stimulates the cedar to witches'-broom 

 formation. Here in these tissues of the cedar the mycelium is 

 perennial, the tissues retaining the fungus year after year with- 

 out being infected anew by seciospores from a pomaceous host. 



Control. 



It is suggested that pear-scab sprayings (see page 335) 

 probably would reduce this disease. Incense cedars should 

 be removed where they are not highly valued, and pear- 

 growers should avoid planting them. As a rule, however, 

 this practice is unpopular, inasmuch as these trees are a 

 valuable forest crop. 



REFERENCES 



Jackson, H. S. A Pacific Coast rust attacking pear, quince, etc. 



Oregon Crop Pest and Hort. Bienn. rept. 1913-1914 : 204-212. 



1915. 

 Jackson, H. S. A new pomaceous rust of economic importance, 



Gymnosporangium Blasdaleanum. Phytopath. 4 : 261-269. 1914. 

 O'Gara, P. J. A rust new on apples, pears, and other pome fruits. 



Science, 39 : 620-621. 1914. 



LEAF-BLIGHT 



Caused by Fabrcea maculata (Le"v.) Atk. 



This disease, which has been called scald and leaf-blight, is 

 known in nearly all countries where the pear is grown. It is 

 recorded from Germany, Sweden, Italy and France, and is 

 especially common in eastern United States. In New York it 

 is most abundant in the Hudson Valley and in the western part 

 of the state, but perhaps even in these regions is less important 

 than farther south and west. It is agreed that pear seedlings 

 are most seriously affected ; in some nurseries their cultivation 

 has been greatly hindered, and in certain cases their growing 

 has been abandoned. In Europe the leaf -blight has been 

 known for at least a century, while in the United States it has 



