30 THE SPRING GRAIN-APHIS OR " GREEN BUG." 



early and the remainder later in the season the latest sown was very 

 much more seriously damaged than that sown earlier. About the 

 only portions of the early-sown part of the field to suffer serious 

 injury were on the poorest soil. In short, the Toxoptera was found 

 to be working its greatest damage in late sown or pastured wheat 

 fields and among the young oats. Natural enemies were busily at 

 work and apparently fast overcoming the pest. 



In the meantime Mr. Ainslie had found the pest destroying wheat 

 in spots in the wheat fields about Fayetteville and Summers, Ark., 

 March 16 to 20, as well as at Chandler, Okla., March 24, and at Guth- 

 rie, Okla., on March 25. Near the latter place large circles were 

 observed in the otherwise green fields of wheat. In the center of 

 these circles the red soil was exposed by reason of the killing of the 

 wheat plants, and these exposed circular areas were bordered by a 

 band or girdle of yellow half-dead wheat plants, where the Toxoptera 

 were most abundant. (See PI. I, fig. 2.) In another field in this 

 vicinity there was a stack of oats straw of the previous year, and from 

 this stack a dead area extended at least 100 feet to the south. This 

 area was nearly circular, with the stack almost in the center of the 

 circumference. Near and surrounding the stack was an area of dead 

 volunteer oats, and beyond this a stretch of bare ground indicated 

 where wheat had once stood. From people occupying a house near 

 by something was learned of the previous history of this straw stack 

 from which Mr. Ainslie determined that volunteer oats had sprung 

 up after thrashing in 1906; these oats turned brown soon after, 

 causing some wonder among farmers, and during the winter the plants 

 died. The trouble spread to the wheat adjoining and here the wheat 

 plants died early in the spring. There was here seemingly a repetition 

 of the conditions in the fields about Summers, Ark., where Toxoptera 

 infesting volunteer oats extended its destruction from these to the 

 wheat near by. 



On March 26, between Guthrie and Kingfisher, Okla., Mr. Ainslie 

 observed that the dead spots in the wheat fields were a striking feature 

 of the landscape, for in the sunshine the bright green of the young 

 grain made a striking contrast with the yellow-rimmed red circles 

 where the Toxoptera had destroyed the wheat. Occasionally a field 

 was free from these areas, but more of them were frightfully spotted 

 in this manner. A field of wheat that was pastured more closely than 

 most grain fields lay in the edge of Kingfisher and showed the attack 

 of the Toxoptera worse than in adjoining grain. On March 27, at 

 Kingfisher, Toxoptera was flying by the millions, the air being full of 

 the migrants, and farmers who drove to town were covered on the 

 windward side to their annoyance. The aphides seemed for the most 

 part to fly low, but the wind hurried them at such a rapid rate that 

 they might easily have been invisible when higher in the air. On the 



