February, '15] 



PRESIDENTIAL ADDRESS, DISCUSSION 



89 



Vice-President Herrick : Personally, I was much impressed with 

 two points — one the emphasis laid upon the desirability of more ex- 

 haustive studies on the life-history and habits of insects. That I 

 think has been emphasized by certain results obtained lately. I think 

 many of us have felt that the extensive work of Professor Slingerland 

 on the peach-tree borer precluded the necessity for any further work 

 on this pest. I understand, however, that further work on the habits 

 and life history of this insect by Professor Scott has enabled him to 

 develop a method of control which is very efficient. This emphasizes 

 the need of further study of the life-history and habits of other insect 

 pests. 



Another point emphasized was more careful studies of insecticides. 

 Undoubtedly Dr. Felt has brought together a good deal of proof that 

 miscible oils are injurious to trees under certain conditions, but during 

 the last two or three years we have applied miscible oils to a great 

 many trees at certain stages, and in no case found injury to these trees. 

 Unfortunately, we do not know just the conditions that bring about 

 injury in some cases and no injury in other instances. This, it seems 

 to me, emphasizes the need of more careful and thorough study of 

 insecticides. 



I hope there will be further discussion of this address. 



Mr. J. G. Sanders: I was deeply interested in one point brought 

 out by the President regarding the necessity for very careful study of 

 all stages of the life history of economic insects; which was empha- 

 sized by the speaker. In our work on the control of the onion maggot 

 in Wisconsin during the past four years, and in working up the lit- 

 erature relating to the control of this species, we have noted a large 

 number of remedies recommended for the control of the onion maggot, 

 numbering I think over sixty. Practically all of these remedies have 

 been recommended for the destruction of the egg or larva already 

 placed on or adjacent to the onion plant, while a few methods were 

 intended as repellents against the adult fly. It seems that no effort 

 had been put forth to kill the adult fly before oviposition. 



In a careful study of the life-history of the onion maggot it was de- 

 termined that a period varying from 10 to 14 days elapsed after the 

 emergence of the adult female before fertile eggs were deposited. It 

 seemed that if an effective means of killing the adult fly during this 

 period could be obtained, it might possibly prove an effective control 

 for this pest. We have determined an effective poison bait spray 

 which works satisfactorily with the adult fly and seems to be a very 

 practical and effective control for the onion maggot, in some cases to 

 the extent of 95 per cent to 98 per cent, while a check plot adjacent 

 was injured to the extent of 75 per cent. 



