FRIT-FLY 189 



The " Green Bug." The spring grain aphis (Toxoptera grami- 

 num Rond.) has of late years caused much injury to grain in Kansas, 

 Oklahoma, Texas, and a few other states where the winter weather 

 is such as to check the growth of parasites which normally keep 

 this pest within bounds, and yet allows the continuous breeding 

 of the louse. Figure 207 gives a good idea of the appearance of 

 this aphid. Winged forms (Fig. 208) are carried northward by the 

 wind, but in northern states it does practically no damage. 



Control. No measures of control are necessary in the northern 

 states where cold winters are the rule. In the South no volunteer 

 grain should be allowed to grow; all such growth should be de- 

 stroyed in the early fall. 



FIG. 207. The "green bug" FIG. 208. The "green bug," winged migrant form. 



(Toxoptera graminum). 



The Frit-fly (Oscinis sp.). This fly (Fig. 209) looks very 

 much like a small house fly. The tiny white eggs are laid in the 

 fall on fall-sown wheat or other grain. The larvae pass the winter 

 within the plant. In regions where spring-sown grain is the rule, 

 the insects hibernate in the larval stage in the straw and stubble. 

 The adults emerge in spring and lay eggs] which produce the 

 first brood of maggots. Another brood of flies emerge during 

 midsummer in regions where fall-sown grain is grown, laying eggs 

 on volunteer grain plants and various grasses, the next brood of 

 flies the fall brood laying their eggs on the young plants of 

 the fall-sown field. 



Injury. Heads of wheat and other grains sometimes wither 

 and die or are filled with shrunken kernels as a result of the work 

 of this insect. Sometimes the stem is cut off by the young maggot 

 within. The presence of the pest is indicated by a premature 



