150 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



(12) It has been found that early plowing of the stubble, at least 

 five inches deep, is not only very effective in controlling the Hessian 

 fly, but is also very successful in promoting a rapid growth of the 

 wheat in the fall, and for this reason wheat may be sowed considerably 

 later on ground that has been plowed early and deep than if it has 

 been carelessly plowed. "When ground is plowed early, plant food is 

 developed very rapidly and water is usually stored in the soil for the 

 growth of the plant. As a result, growth is rapid, the plants tiller 

 abundantly, and strong roots are developed before winter. Rather 

 late seeding on a well prepared seed-bed will give much better yields 

 than early seeding on poorly prepared ground even when no Hessian 

 flies are present. Also, wheat that has made a good growth is better 

 able to resist attacks of the fly, since it tillers more and there are 

 more stalks to take the place of those destroyed." ^ 



(13) Since many of the flies migrate considerable distances, early, 

 deep plowing, to be effective, must be practised by the entire neigh- 

 borhood in such a manner as to include all infested fields, and since it 

 is usually impractical to plow all fields in a neighborhood early and 

 deep, the only way to insure safety from the fall brood of fly is to sow 

 after the fly-free date. 



(14) Late sowing alone will protect most of the wheat in the fall 

 from becoming infested by the fall brood of the fly, but it should be 

 remembered that there is also a main spring brood and, if any volun- 

 teer is growing in the main field of wheat, or in the old stubble fields 

 left to plant to some other crop the next spring, or if there is a field of 

 early sown wheat nearby, the spring brood of flies, emerging from the 

 infested plants about the first of April, is very apt to infest the late 

 sown crop, and thus wheat absolutely free from fly in the fall may 

 become dangerously infested next spring by the spring brood (Table 

 IX). In Kansas, in the springs of 1915 and 1916, hundreds of cases 

 of this sort were true and it will probably always be true of any year 

 when there is a general infestation over the whole neighborhood. The 

 Hessian flies will migrate in dangerous numbers for several miles, 

 hence the importance of community cooperation cannot be over- 

 emphasized. One man with a field of volunteer or with a field of early 

 sown wheat may endanger a number of wheat fields which were free 

 from infestation in the fall. 



(15) In Kansas, the important steps in the control of the Hessian 

 fly are: (1) early, deep plowing of the stubble; (2) the proper prepara- 

 tion of the seed-bed; (3) destruction of all volunteer wheat; (4) delay 

 the sowing until the fly-free date; and (5) cooperation. 



^ Bui. 213, Kansas Experiment Station, 1916. 



