DISEASES OF PEARS 



1051 



FIG. 326. LEAF 

 BLIGHT ON 

 QUINCE 



The disease causes a spotting of the leaves, twigs, and fruit. 



The spots on the leaves are small and on the upper surface show as 



reddish circular areas surrounded by a dark 



border. Later the spots become dark-colored, 



and a minute elevation may be seen at the 



center. When the attack is severe, the leaves 



become yellow or brown and readily fall off. 



The spots on the leaves can be distinguished 



from leaf spot because they are smaller, 



more circular in outline, and more brightly 



colored, especially when young, and also by 



the absence of the numerous minute black 



bodies. The spots on the fruit are red at 



first but become dark-colored later. The 



fruit may become cracked as a result of the attack much as- when 



badly affected by scab. The appearance of the disease on the 



twigs is similar to that on the leaves. The spot may enlarge so 

 as to encircle the twig, thereby causing it 

 to die. Quince stock and pear seedlings are 

 said to be especially susceptible. 



The disease is caused by the fungus 

 Fabrea maculata, which produces its sum- 

 mer spores in the center of the spots above 

 described. These are disseminated in the 

 moist weather of summer. The fungus may 

 winter over in the infected twigs, but infec- 

 tion in spring is commonly brought about 

 by sexual spores produced on the fallen 

 leaves in which the fungus has wintered. 



Either bordeaux mixture of standard 

 strength or lime-sulphur solution 1-50 ap- 

 plied as for pear scab, will control the dis- 

 ease should it appear in the orchard. 



FIG. 327. LEAF 

 BLIGHT ON 

 FRUIT OF PEAR 



