EXPERIMENT STATION BULLETINS. 



651 



July and August was very typical. (Fig. 4), This production of 

 characteristic signs is of importance since Lntman*, who ascribes tip- 

 burn to excessive heat and sunshine, was unable to produce artificial 

 burning in a greenhouse during the month of April and attributed his 

 failure to weakness of daylight during that month. 



Fig. i. Potato leaf showing hopperburn produced by leafhopper nymphs in greenhouse experiment with caged plants. 



skins of nymphs are seen clinging to the leaf. 



Cast 



HOPPERBURN AND TIPBURN 



The word "hopperburn" as a name for the specific injury caused by 

 the leafhopper, Empoasca mail was coined at the December 27, 191S 

 meeting of the War Emergency Board", following the presentation of 

 Dr. Ball's results to that body of plant pathologists. The possibility 

 that not all burning injury of potato leaflets was due to the leafhopper 

 led to the reservation of the general term "tipburn" for the condition 

 of which hopperburn was a subdivision. Concerning the type of burn- 

 ing which occurs in Vermont (Lntman*) and Maine (Folsom and 

 Schultz ^), the writer is not attempting an opinion. It may be said that 

 "hopperburn" and "tipburn," as shown by pictures and descriptions, 



