April, ’20] 
BALL AND FENTON: LEAFHOPPER AND TIPBURN 
221 
Mr. E. D. Ball: About the 5th of May. 
Mr. Leonard Haseman: What produces the injury of either 
tipburn or hopperburn or the curly leaf of beets? 
Mr. E. D. Ball: Those are two diseases that we know to be 
caused by insects and can be produced in no other way; but what 
produced them is a subject on which no pathologist or physiologist will 
even hazard a guess, so for a mere entomologist to make a suggestion 
would be far out of place. 
Mr. Cromwell : I would like to ask what the comparative amount 
of leafburn was in 1919 and 1918 in Iowa. 
Mr. E. D. Ball: I was not in Iowa in 1918, except in the fall of 
the year, when it was approximately the same as during the fall of 
this year. It was a little worse during the hot period of the summer, 
I am told, in 1919. Our potato crop in Iowa this year was nearly a 
failure, more so than it was the year before. 
Mr. H. A. Gossard: I would like to ask Dr. Ball whether or not 
he ascertained to his satisfaction that the group of females were doing 
all the burning. 
Mr. E. D. Ball: That was a point that we were not able to deter¬ 
mine. The handling of a very minute leaf hopper like this proved to 
be one of the most difficult problems we had ever attacked. So much 
individual work was required that we did not have opportunity to 
carry these tests farther. 
Mr. W. 0. Hollister: You might be interested in a little experi¬ 
ence I had with the leaf hopper on the soy bean. I had some plants in 
the laboratory entirely free from any organism or insect. One leaf- 
hopper placed on the central stem of a plant produced an entire wilting 
and the leaf collapsed in fifteen minutes. 
Mr. J. R. Parker: The control has not been discussed. 
Mr. E. D. Ball: Mr. Dudley’s paper deals with that. I visited 
him this summer, and he told me that he used nicotine sprays and 
got almost complete control. I wish, however, that we might leave 
that until Professor Parrott’s paper comes up. 
Professor Dudley got control with tobacco solutions. I cannot 
give you the details, but his paper will undoubtedly give that when 
you have it. Professor Parrott obtained control with the Bordeaux 
solution. It is a fact that we had very much heavier infestations in 
Iowa. 
President W. C. O’Kane: The next paper will be presented by 
Mr. W. E. Britton, on “ A Connecticut Corn Field Injured by Crambus 
prcef ectellus Zinck.” 
