50 



with the Hessian fly; they are larger and of a more glassy green color 

 than those of the lesser wheat stem-maggot, and it is only when still 

 very young that the ordinary farmer need ever mistake them for any 

 of the others mentioned in this bulletin. It is only in the manner of 

 killing the stem of young wheat that it need be confused with others. 



EXTENT OF RAVAGES. 



Though present in the fields every year, as is witnessed by the 

 whitened heads of grain in the fields just prior to harvest, I have never 

 known a serious attack at that season of the year; nor is there any- 

 thing at present to indicate that it is likely to work more serious 

 injury at this season in the future than it has in the past. 



Its ravages in the young wheat in fall and spring, as illustrated by 

 the outbreak in Illinois in 1882-83, are not as yet of usual occurrence, 

 though several similar instances have come to my knowledge within 

 the last twenty years. In two cases — one in Indiana in 1888 and 

 another in Ohio in 1900 — the fields were also badly infested by Hes- 

 sian fly, but from the material reared it would seem that this species 

 was to be credited with no small percentage of the loss. Occasionally 

 fields of fall wheat, especiallj^ if sown early, are attacked in the fall 

 and ruined by this insect alone, though the damage is in some cases 

 attributed to the Hessian fly. It is, however, easy enough to detect 

 the difference between injuries caused b}^ these insects, as has been 

 explained under methods of attack. 



^ PREVENTIVE MEASURES. 



The liability of attack from this insect is not sufficiently great to 

 warrant any expensive measures being put forth in order to forestall 

 possible outbreaks. As yet, we have no wa}' of foretelling these sud- 

 den attacks, as the pest has never proven excessively abundant in the 

 same locality two years in succession. The fact that late-sown wheat 

 is less subject to injury, and in cases where the two have been found 

 in a combined attack, the grain has been sown early, indicates that this 

 now-accepted method of warding off an attack of Hessian fly will work 

 equally well with this species. There is nothing at present to indicate 

 any change from these conditions throughout the winter-wheat grow- 

 ing regions of the Northern States. Whether or not the same rule 

 will apply in the South remains to be seen, as we know too little of 

 the pest in that portion of the country to be able to speak positively. 

 In the North, in the regions devoted to the raising of spring wheat, it 

 would appear that a burning over of the grass lands in winter would 

 reduce the probabilities of attack. The destruction of volunteer wheat, 

 which should be done in any case as a protective measure against 

 attacks of Hessian fly, will of course tend to reduce the probability of 

 the young wheat being attacked in autumn. It must be borne in mind, 



