64 ENTOMOLOGICAL SOCIETY. 



THE COTTON BOLL- WORM IN CANADIAN CORN. 



By J. Dearness, London, Ont. 



On the 10th of October Mr. E. T. Shaw, residing near Dorchester Station on the 

 G. T. R., east of London, drew my attention to a larva which he said was damaging his 

 corn by burrowing from the top downward between the rows of grain on the ear. I 

 went over into the field — one of about four acres — and with his assistance soon obtained 

 a number of specimens of the larva. I estimated that in the part of the field we were 

 collecting them that about one ear in five wag affected. 



On taking the larvae home I was surprised to find that it agreed exactly with the 

 descriptions of the Cotton Boll worm ( Heliothis armiger Hubn^ and that in a Canadian 

 latitude it could be so numerous as to possess an economic interest. 



On making further inquiries I learned that the " worm " was reported in the corn- 

 fields of most of Mr. Shaw's neighbors and indeed was said to be much more prevalent 

 and injurious in a large corn-field of Mr. McNiven's than in Mr. Shaw's. 



Last week Mr. Paul Hunter informed me that he had been husking corn in a field 

 near Gladstone, Ont., a village in another part of the same township, and that " nearly 

 every ear had a worm in it." He described the insect so well without any suggestions 

 from me that I felt sure it was the same that had attracted the attention of the Dor- 

 chester Station farmers. 



I visited Mr. Shaw's farm again on the 3rd instant (November) in the hope of find- 

 ing some morn specimens, the numbers of my first collection having been reduced by 

 cannibalism. In confinement the larvae seem to prefer the tissues of each other's 

 bodies to the corn I placed in the jars with them. Possibly, indeed probably, they 

 could not bite the rather hard shelled corn placed in one of the jars. In another jar 

 in which two or three ends of ears of corn had been placed, when I returned after a 

 week's absence only one specimen was living. Therefore, as just stated, I went last 

 week to Mr. Shaw's to collect some fresh specimens to bring to this meeting. He 

 happened that day to be hauling in unhusked corn. In the load just brought in we 

 found relatively few affected ears, not more than one in twenty or thirty, but in the 

 next load they were quite common, one in every two or three ears. 



The affected ears usually had but a single larva in them, the largest number I 

 saw in one ear was three. The damage done to affected ears by the burrowing and 

 milling of the grain is not very great, less than five per cent., but some of such ears 

 showed a mould that had made an entrance and was following the channel burrowed 

 between the rows of the injured grains. 



Dr. Fletcher informed me last night that a farmer near Orilla had reported dam- 

 age to 75 per cent, of the ears of his corn by an insect which the doctor found to 

 be the same species as the one under consideration. He will doubtless refer to it in 

 his Notes of the Season. 



The life-history of this interesting insect has been so well studied and so fully 

 reported in the Fourth Report of the U. S. Entomological Commission and in subse- 

 quent bulletins of the Division of Entomology of the U. S. Department of Agricul- 

 ture that but little remains to be done by Canadians. However its appearance here in 

 the role above described may justify a brief synopsis of what has been recorded of its 

 history and habits. 



From the elaborate report of the Commission above cited we learn that in many parts 

 of the Southern States the Boll- worm is regarded as more destructive to cotton than all 

 other insects combined and that in some parts of the Southern and Western States it has 

 been very injurious to corn. In the three years preceding the labors of the Commissioners 

 they reported very marked damage to corn all through the South and West, it being a 

 common experience to find fields in Virginia and southward in which almost every ear 

 was pierced. 



