176 EXPERIMENTAL FARMS. 



heads " are also caused by the attacks of a Frit-fly {Oscinis soror, Macq.), the maggot of 

 which is described as boring inside the lower portion of the culm. Throughout the pro- 

 vince, although many enquiries were made, there were far fewer complaints of " dead 

 heads " this season than last, 



Mr. Peter Elder, of Blyth, near Rounthwaite, Man., showed me all through one of 

 his large fields where last year a serious loss occurred from " dead heads," and not a 

 trace was this year to be seem. Mr. A. C. Hawkins, of Swan Lake, Man., cited in my 

 last report, writes : " Sept. 10. — According to promise, I endeavoured to procure speci- 

 mens of the larva causing damage to wheat, known as ' dead heads ' ; but the only sign 

 of insect work I found was an empty cocoon a little over ^ of an inch long and yellowish- 

 white in colour. (Undoubtedly of Wheat-stem Maggot.— J. F.) There were very few 

 ' dead heads ' in the crop." Mr. George C. Mannix, of Stonewall, who suffered last 

 year, also writes : " I am happy to say there are no ' white heads ' in the wheat this 

 year," 



References to " dead heads " made by Manitoban farmers all speak of this injury 

 as being a new one, and, judging from the behaviuur of the Wheat-stem Maggot in 

 Ontario, and in Manitoba during the past season, I think it may be confidently hoped 

 that this is not going to be a constant source of loss to the wheat farmers of the West. 

 The insect feeds naturally in the grasses of the prairies, to which under ordinary 

 circumstances it will chiefly resort, and I believe that its attacks upon wheat occurring 

 .so occasionally are due to climatic conditions which are not likely to occur every year. 

 Moreover, wherever I have collected the mature flies by sweeping the prairie grasses 

 with a collecting net, I have invariably found large numbers of its special parasitic fly, 

 Ccelinius meromyzce, Forbes. Notwithstanding the above, however, Prof. Otto Lugger, 

 of Minnesota, who has also studied it in his State, where in 1895, 1896 and 1897 it was 

 common from the Red River valley to the central part of East Minnesota, says that it 

 threatens to become in the future a serious enemy of their crops of small grain. " In 

 some parts of the State the late sown rye, which had made but little growth during the 

 autumn and which grew slowly in spring, was greatly damaged, in some cases to the 

 extent of one-tenth of the crop. Wheat did not entirely escape, and the plants infested 

 by the insects showed their presence by their small size and general weakly appearance." 



Remedies. — (I.) Should the attack of the Wheat-stem Maggot increase seriously 

 and its presence be shown by the " dead heads," certainly much may be done towards 

 reducing the numbers of the next brood by sowing a drill or two of wheat or barley 

 in close proximity to the infested fields. This should be sown as soon as the injury is 

 detected, so that the young plants may be up in time to attract the females for egg 

 laying. After the middle of August these strips should be fed off by sheep or ploughed 

 down. All stubble should be harrowed as soon as possible after the crop is carried, so 

 as to start a volunteer crop, which should be ploughed down early in September, The late 

 sowing of fall wheat, where this crop is grown, could not profitably be delayed long 

 enough to escape the egg-laying period of the last brood. 



(II.) The application of special fertilizers as a top dressing when young wheat is 

 known to be attacked, will help injured plants to throw out new stools and overcome to 

 some measure the effects of the attack. 



The American Frit-ply (Oscinis carbonaria, Loew.). — The maggot of this enemy of 



the wheat is only -^^ of an inch in length and yel- 

 lowish-whiie in colour. These maggots may be 

 found in autumn destroying the bases of the stems 

 of several kinds of grasses and of fall wheat. They 

 also occur in spring wheat and grasses in June, at- 

 tacking the young root-shoots close to the ground 

 and either destroying or seriously weakening 

 them. Some eight or ten years ago the American 

 Frit-fly was the cause of extensive and widespread 

 loss in Canadian wheat fields, but since that time 



Fig. 5.-The American Frit-fly- j^^^jj ^ mention of it has been made by cor- 



enlarged. -^ , , . , , •' . , 



responaents ; nor have its attacks been noticed 



