492 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 14 



Percentage of Straws Infested by Harmolita vaginicolum 



Sowed Sept 3 0% 



9 Trace 



" 16 '• 



"20 " 



" 23 " 



Oct 2. 



" 14. 



" 23. 



Spring Wheat. 



Too young to detect . 



1% 

 10% 

 22% 



191S 



Trumbull County 

 (Experiment Farm) 



Sowed Sept 4 0% 



15 Trace 



" 22 11% 



Oct 1 19% 



" 10 32% 



Spring Wheat 21% 



Too young to detect. 



Sowed Sept 9 0% 



■■ 18 0% 



' 23 0% 



Oct 1 0% 



" 10 0% 



Spring Wheat 67% 



Mahoning County 

 (Stooksberry Farm) 



Sowed Sept 2nd week . 

 Oct. 1st week. . 

 Nov 1st week. . 



3% 

 16% 



44% 



1919 



1920 



(Experiment Farm) 



Sowed Sept 4 0% 



"18 0% 



"23 3% 



"30 5% 



Oct 11 28% 



" 20 44% 



Sowed Sept 2 Trace 



" 12 0% 



" 19 Trace 



" 30 " 



Oct 10 5% 



" 22 19% 



Sowed Sept 29 Trace 



Oct 7 " 



:' 15 i% 



' 26 1% 



Nov 5 2% 



Spring Wheat 1 % 



Sowed Sept 1 J<% 



" 10 H% 



" 20 1M% 



Oct 4 3% 



" 9 6% 



" 20 11% 



Spring Wheat 7% 



Too young to detect. 



From the data in the tables, it is seen that a very good control is 

 secured in northeastern Ohio by avoiding the sowing of wheat after 

 October 1st. Late sowed wheat and spring wheat suffered the most, 

 the latter being very severely damaged, altho this damage did not show 

 up until after the winter wheat was harvested. 



The control of this species does not necessarily conflict with the 

 control of hessian fly, when we consider that the fly-free sowing dates 

 for this section of Ohio commence about September 23rd. There is 

 then a period of time between the first fly-free dates and the first date of 

 serious infestation from H. vaginicolum, during which time wheat may 

 be sowed and avoid both insects. The length of this period apparently 

 varies with the season, but it is usually sufficient to avoid a serious 

 outbreak of either. In most years, sowing during this period of 

 immunity will give protection from both of these insects. 



