24 



IN EXPEEIMENTAL SOWINGS. 



For the purpose of securing more precise and complete data 

 concerning the midsummer history of the fly in Southern Illinois, 

 I selected for experimental midsummer sowings a field near Edge- 

 wood, in Efiingham county, belonging to Mr. J. Lundberg, and 

 one belonging to Mr. Aaron Young, at Billett Station, in Law- 

 rence county, both of which had been too badly damaged by the 

 fly to repay harvesting. These were, in fact, the only fields I 

 was able to find in Illinois where the damage was last year suf- 

 ficient for my purpose. 



The Lawrence County Field.— The history of this field was 

 thus reported to me by the owner. It bore its first wheat in the 

 summer of 1885 — an excellent crop, showing no sign of the fly at 

 any time. After harvest, the stubble was plowed between the 

 5th and 10th of July, and considerable volunteer wheat sprang 

 up which became badly infested by the fly. This wheat was 

 allowed to stand until the last week in October, when the 

 ground was sowed again to wheat, put in with a double-shovel 

 plow. This grain started well, but became, notwithstanding, some- 

 what infested with the fly that fall (1885), and May 1 of the 

 following spring was seen to be badly damaged. On the 15th 

 May, 1886, it contained great numbers of naked larvae, with a 

 few freshly formed puparia. From these larvse, transferred to 

 our breeding cages, we obtained several imagos May 28, and June 

 8 and 17. The wheat was so badly damaged that it was not 

 harvested, but was plowed up in June and the ground planted in 

 part to melons and in part sowed to wheat for my experiments.* 



Your successive experimental sowings were made for me by Mr. 

 Young, on lots each about one rod wide and ten rods long, the 

 stubble being each time plowed for the purpose immediately before 

 sowing. The first, made July 13, 1886, came freely, but was soon 

 nearly all killed by a violent attack of a new, third brood of the 



Enough remained, however, to afford a suflicient temptation to any 

 flies that might be abroad in search of a place of deposit for their 

 eggs. The second sowing, made July 28, suffered like the first. 

 Between these two sowings, a neighboring [field of wheat stubble 

 was i>lowed, and soon produced a good growth of volunteer wheat,, 

 which was of great use to us later. 



The third and fourth sowings, made August 5 and 19, grew well',, 

 and received no damage until attacked by the fly. 



•In a flold adjacent, sowed October 10— much earlier, that is, than the infested wheat— no fly 

 appeared eltlier in fall or spring, but the srain was headed flndy May 15, and ultimately made a 

 Rood croj). ItBeeiiis highly probable, therefore, that the tiies which doi)()alted their egKS in the 

 later wheat came only, or « hie(iy, from the volunteer wheat in the fall of ISHf), nnd that if these had 

 been killed by complete and timely destruction of the volunteer wheat itself, the subHeipient dam- 

 age would have been i)revented It is also a]»parent that the remarkabh; fact of the deHtrnction of 

 the late sonn wheat, while early sown wheat beside it escaped, is to be sinnlarly accounted for. In 

 the volunteer wheat the liy passed the period of early frosts in the relatively hardy state of larva, 

 orpupariiim. emerKiuK later as the delicate and susceptible win^yed iiiiaffti. and llnding time be- 

 tween frosts to deposit its eKgs In the young grain aniid which It came to light. 



wheat bulb worm, Meromifza 



detailed elsewhere. 



