146 



DISEASES OF ECONOMIC PLANTS 



be of serious import, although its increase at any time under 

 favorable chmatic conditions may place it among the im- 

 portant plant enemies. 



CRANBERRY i 



Scald, blast (Guignardia Vaccinii Shear). — The fruits 

 are attacked as soon as the blossom falls, or even the 



Fig. 62. — Cranberry scald and blast. After Shear. 



blossom itself may be blighted. The affected berry 

 shrivels, turns black, and is covered with pycnidia. 

 From such fruits the disease spreads to other fruits and 

 to the leaves. In some bogs as much as 50 per cent of the 

 crop is thus destroyed. This form of disease is commonly 



' The information given here is taken largely from Shear, C. L., U.S. 

 Dept. Agr. Bur. Plant Indus. Bui. 1 10, and Halsted, B. D., N.J. Agr. Exp. 

 Sta. Bui. 64. 



