August, '22] FENTON & RESSLER: ARTIFICIAL PRODUCTION OF HOPPERBURN 



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were crushed on the leaf tissue or leaf petioles and in which the rnace- 

 rated leafhopper juice was drawn into the leaves by leaf transpiration. 



What is Hopperburn 



There are several types of injury found on potato leaves 

 which are characterized by the death and furring brown of the 

 leaf tissue. These have often been confused and described under 

 the general term tipburn. The writers believe that much of the 

 skepticism concerning the recent work on hopperburn is because 

 of a failure to distinguish between these various leaf disorders. It 

 therefore seems advisable at this point to describe briefly the injury 

 which should be characterized as hopperburn and to compare it with 

 other related leaf burns. Hopperburn always begins at the margin 

 of the leaf and the burning is correlated with the veins. This relationship 

 is not evident in older hopperburned leaves but is easily seen in the 

 earlier stages (Fig. 15, 1-4) when the triangular or diamond shaped areas 

 are seen to run in from the margin and to follow the veins. Other 



Fig. 15 — ■Comparison of hopperburn with other leaf burns. 1-4. Successive 

 stages of hopperburn ; 5. tipburn (after Lutman); 6. scorching; 7. sunscald; 

 8. greenhouse burning. 



