6 Farmers’ Bulletin 1225. 
INJURY CAUSED BY THE POTATO LEAFHOPPER. 
FEEDING INJURY. 
Adults and nymphs of the potato leafhopper, in common with 
other sucking insects, extract the juices or sap of plants by means 
of their delicate beaks which they insert into the epidermis of the 
leaves. The injury thus caused through loss of plant juices is 
considerable and alone would cause the leaves to turn yellow. 
When a large number 
of leafhoppers are 
present the plant will 
sometimes wilt. 
‘“HOPPERBURN.”’ 
In addition to the 
injury caused by loss 
of plant juices this 
leafhopper is the cause 
of a distinct injury 
called “hopperburn”’ 
which follows its feed- 
ing on potato and 
many other plants 
(fig. 3). 
The first symptoms 
of “hopperburn”’ are a 
slight yellowing, usu- 
ally of the tip of a leaf. 
As the disease pro- 
eresses the leaf slowly 
turns brown, curls up- 
ward, and dies. The 
disease spreads from 
the tip or margin toward the midrib of the leaf, but spreads more 
slowly toward the base, and the basal area may remain green until 
the whole plant is nearly dead. 
During periods of hot, dry weather ‘“hopperburn’’ spreads rapidly 
and whole fields of early potatoes may be killed in a week’s time 
(fig. 4). On the other hand, during cool, moist weather, or where 
protective sprays have been applied, the disease is checked and 
throughout the summer may progress no farther than the primary 
symptoms (fig. 5). 
It has been found that even one or two leafhoppers placed on a 
healthy potato plant covered with a cage were able to cause suffi- 
cient “hopperburn”’ to kill the entire plant, while other caged plants 
kept free of leafhoppers remained healthy. 
Fig. 3.—Potato leaf affected with ‘“hopperburn.” Upper surface 
of leaf showing typical upcurled brown tip and margin, 
