252 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



jury by the spring brood depends directly upon the amount of volun- 

 teer wheat present at seeding time. Hence, the importance of destroy- 

 ing this. 



Hessian Fly Control 



Number of fields examined 306 



Number in wheat 1915 and 1916 273 



Number in wheat 1916, other crop 1915 33 



Number sowed before the fly-free date in 1915 64 



Per cent sowed before the fly-free date in 1915 20.9% 



Number sowed after the fly-free date in 1915 242 



Per cent sowed after the fly-free date in 1915 79 . 1% 



Table I 

 Sowed before the fly-free date with or without volunteer wheat in seed-bed: 



Infesta- Number Per cent of 

 tion Fields Fields 



SUght 15 23.4 



Medium 12 18. S 



Heavy 37 57.8 



Table II 

 Sowed after the fly-free date with no vohmteer wheat in seed-bed: 



Table III 

 Sowed after the fly-free date with a medium amount of volunteer wheat in seed-bed: 



Infesta- Number Per cent of 

 tion Fields Fields 



SUght 46 44.2 



Medium 40 38.5 



Heavy 18 17.3 



Table IV 

 Sowed after the fly-free date with much volunteer wheat in the seed-bed: 



No protection to the crop was noticed where the stubble had been 

 burned over in 1915 and observations made in this county in 1916 give 

 little encouragement from this source. The flaxseeds were too low on 

 the stubble to be destroyed in large numbers. Less than 1 per cent of 

 the acreage under surv^ had been burned in 1915 previous to plowing. 



