180 Frit Fly in Relation to Blindness m Oats 



It is apparently loosely attached though undoubtedly as securely as 

 in the stem or grain attacks. When the panicle pushes out of the en- 

 closing leaf and still more as the panicle itself expands, the pupa is 

 almost invariably forced off and falls to the ground. Many pupae were 

 obtained during the season still attached to the open panicles, but the 

 proportion was very small, so that had the attack been mild or only 

 moderately severe, it would have been very difficult to have found any 

 at all. 



An examination of the field therefore seldom gives any indication of 

 the cause of the trouble. 



Whether the imagines emerge from pupae on the ground or at the 

 time the ears are unfurling cannot be answered definitely at present, but 

 from the dates of hatching of those obtained one would almost conclude 

 from the ground. 



The first fly was hatched indoors on July 2nd, but the main bulk 

 appeared later, approximately the third week in July. This period it 

 must be understood is based on the year's observations only, and most 

 of the specimens were gathered on an area where the dates of sowing- 

 varied from March 28th to May 13th giving therefore almost as wide a 

 range of maturing of the crop as it is possible to get. 



Varieties op Oats. 



The data given above were obtained on a field of Abundance oats, 

 but examination of oat fields over many farms on a wide area fully 

 supported them. A careful study was made of a number of oat varieties, 

 sown on the same day (April 9th), and grown side by side, to see if variety 

 had any effect on the intensity of the " blindness " attack. 



The results are given in the table below. 



