QUINCE DISEASES 389 



although it does not necessarily bring about serious diffi- 

 culty. Yet in nurseries defoliation is common, and some- 

 times twigs are girdled. The quince orchards in New York 

 State suffer rather severely, especially those in sod or those 

 which are otherwise neglected. Even well-managed orchards 

 are not always free from the disease. All varieties are sus- 

 ceptible. 



Symptoms. 



Like -the spots on pear leaves, there is produced a more or 

 less circular discoloration on the upper surface, with a reddish 



FIG. 113. Types of lesions on quince-leaves produced by the leaf-blight 



fungus. 



center and dull borders (Fig. 113). Finally the lesion extends 

 through the leaf-tissue showing on the lower surface. The spot 

 on the upper surface becomes dark-brown and a characteris- 

 tic blackish elevation appears in the center, the fruiting 

 pustule of the pathogene (Fig. 113). When the spots are 

 numerous, they coalesce (Fig. 113) ; in cases of severe attack 

 the leaves turn yellow and fall. This defoliation is common in 

 August and September. As a result of a serious infection the 

 quince fruits remain small and the next year's crop suffers. 

 The lesions on the twigs are similar in appearance to those on 



