Bui. c4, U. S. Dept. of Agriculture. 



Plate VIM. 



Fig. 1.— Leaf-Roll in Seedling Potato No. 16518, Alexander No. 1 Red X 

 Keeper. _ Washington, D. C, August, 1912. 



Fig. 2.— Potato Leaf-Roll, Showing Its Effect on Tuber Formation. Stolons 

 Thickened and Producing Numerous Small Tubers Only. Mitchell, Nebr., 

 September, 1911. 'Photographed by Fritz Knorr.) 



