Bui. e4, U. S. Dept. of Agriculture. 



Plate IV. 



FiQ. 1 .—Typical Potato Leaf-Roll in Seedling No. 16472, Alexander No. 1 

 Red X Keeper. Houlton, Me., August, 1912. 



Fig. 2.— Potato Leaf-Roll. Advanced Stage in Seedling No. 304, Geheimrat 

 Thiel X Keeper. Houlton, Me., August, 1912. 



