150 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



associated with the abundance of the pest. When the parasites 

 become abundant they will often completely rid a field of the 

 aphides within a few days. All of the common ladybird-beetles 

 (Coccinellidce), Syrphus-fly larvae, and lace- winged fly larvae 

 (Chrysopidce) are commonly found feeding upon the aphides. 

 Control. No practical remedy for this species is known nor 

 are means of control easily suggested. The suppression of 

 volunteer wheat and oats in early fall will prevent the multiplica- 

 tion of the pest before fall-sown wheat is available, and the late 

 sowing of wheat in the fall will reduce the numbers entering 

 hibernation. A wise rotation and the thorough preparation 

 of the seed-bed and liberal fertilization will be of value in avoid- 

 ing injury in the same way as has been described for other pests 

 of small grains. Fortunately this spscies rarely does very wide- 

 spread injury and its parasites usually soon bring it under control. 



The Spring Grain-aphis or Green Bug * 



Though long known as a serious pest of small grains in Europe, 

 this aphis has done widespread injury in this country only during 

 the past ten years. Though it occurs throughout the territory 

 north of latitude 41, with the exception of the North Atlantic 

 States, as far west as longitude 105, the worst injury has been done 

 in northern Texas, Oklahoma, and Kansas, though it has also been 

 injurious in the Carolinas and Tennessee. 



The habits of the insect during the winter have not been suffi- 

 ciently studied to- speak authoritatively, but it seems probable 

 that it normally passes the winter in the egg stage, the small shin- 

 ing black eggs, one-fortieth inch long, being laid on the leaves in 

 the late fall. In the South, however, it often continues to 

 reproduce throughout the winter, and with a mild winter the 

 numbers so multiply that unless checked by parasites serious 

 injury is done by late winter or early spring. Both wingless and 

 winged forms occur throughout the year. The wingless female 

 is from one-twenty-fifth to one-fourteenth inch long, yellowish- 

 green, with a median line slightly darker, eyes and most of the 

 * Toxoptera graminum Rond. Family Aphididce. 



