February, ’18] 
ENTOMOLOGISTS’ DISCUSSIONS 
85 
In sections where the onion fly occurs and where climatic conditions 
are more favorable to poisoned bait applications, further trial is strongly 
recommended. 
President R. A. Cooley: We are grateful for this contribution to a 
perplexing problem. Do you wish to ask questions or discuss this 
paper? 
Mr. T. J. Headlee: I am under the impression that the investiga¬ 
tor didn’t have very good success. We have had two years’ experience 
with it on the Sanders’ plan and we have had a good deal of success. 
We are very enthusiastic about it. 
Mr. N. F. Howard: I would like to ask Dr. Headlee if climatic 
conditions in New Jersey, where the experiment was tried, were similar 
to those in Wisconsin which I described. 
Mr. T. J. Headlee: We had some rain, about fifty inches during 
the year; but I can’t say we had continuous rain. 
Mr. N. F. Howard: I should like to ask in what way the results 
were checked, how far from the fields were they treated, and what evi¬ 
dence there was that less injury on the field was not due to different 
conditions. In our experiments we found that we had to use great 
care in choosing a check. We have found the flies in the center of 
Green Ray, a mile and a half from onion fields, and in cruising out on 
Green Bay we found them on the side of the boat. Whether they 
were there at the time we left town or not, we don’t know. 
Mr. T. J. Headlee: This work was done as more of a demonstra¬ 
tion and there were no plants immediately adjacent to the field, but 
there were several growing sections, and the treated areas, while 
pretty well removed, were perhaps within half a mile and outside of 
that area there were numerous fields with serious injury. There was 
no effort to carry on an experimental test. Where the treatments were 
applied, we didn’t have any trouble; where the treatments were not, 
we did. 
Mr. N. F. Howard: Several growers in the district where I worked 
in 1915 and 1916 recommended very strongly this method after trials 
in 1914; but the onion maggot infestation in Wisconsin in 1914 was 
very light and in 1915 it was very heavy and no benefits were gained 
from the application. In 1916 the infestation was still heavier and we 
noticed no results at all as a result of the application of this method. 
Mr. J. G. Sanders: It must be remembered that our first test of 
this method of destroying the onion maggot was at Racine, where we 
had a rather dry, early growing season. Now Racine, Wis., is only 
a few miles above Chicago and the conditions there for testing this 
material were almost ideal. When I asked Mr. Howard to carry on 
