10 Farmers’ Bulletin 1225. 
Plants of all the foregoing varieties which were caged and kept 
free of leafhoppers showed no symptoms of “hopperburn”’ during a 
period of two months (fig. 7, A and B). 
Observations made in several potato-growing sections of Wisconsin 
have shown that the Triumph variety is invariably more severely 
affected with “‘hopperburn” than any other variety grown com- 
mercially in that State. Usually the Rural New Yorker has been 
found to be the most resistant to “hopperburn” of any variety 
grown commercially in Wisconsin. 
i 
Fic. 8.—Hopperburn” accompanies leafhopper feeding. Apple seed- 
ling atleft, covered with cage containing leafhoppers, developed ‘‘hop- 
perburn”’ in a few days. Seedling at right, covered with cage free of 
leafhoppers, remained healthy. 
FOOD PLANTS. 
The potato leafhopper visits a considerable number of plants for 
feeding purposes. The more important economic plants on which 
reproduction takes place and ‘‘hopperburn”’ occurs are the following: 
Potato, beans (practically all varieties), sugar beet, hemp, apple, 
and raspberry. It also attacks several ornamental trees and shrubs. 
Reproduction appears to take place most readily on potato, with beans 
as asecond choice. Hemp, sugar beets, and apple nursery stock are 
more liable to severe injury when growing near potato or bean fields. 
