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 
