168 



DISEASES OF ECONOMIC PLANTS 



essarily cause the death of the whole leaf, though it may 

 do so. 



Upon shoots the same characteristic appearance is noted 

 as upon the lower surfaces of the leaves. Sometimes the 



Fig. 72. — Young Niagara clusters attacked by brown or gray rot. After Lodeman. 



death of the affected twig or even of the whole vine results. 

 Immature berries which are affected stop growing and de- 

 velop the same coating noted upon the leaves, giving rise to 

 the name " gray rot." If the berries be more mature when 



