54 REPORT OF THE STATE ENTOMOLOGIST I92I 



Comparison of average percentages of infestation by Hessian fly 



County 



Albany 



Cayuga 



Chautauqua 



Clinton 



Columbia 



Cortland 



Dutchess 



Erie 



Genesee 



Livingston 



Monroe 



Niagara 



Onondaga 



Ontario 



Orange 



Orleans 



Rensselaer 



Seneca 



Tompkins 



Ulster 



Wayne 



Wyoming 



Yates 



I0I7 



1918 



iQtg 



jgso 

 6.12 



IQZI 





I. OS 



939 



6.67 



6.93 





1.47 





4.48 

 2.60 







.42 





10.72 



9-97 





.84 



4-39 









.17 





16.33 





4 



1.73 



3.87 



14-79 



8.23 





1. 19 



IS. 77 



29.82 



7.61 





1. 19 



S.91 



16.37 



4.29 



4 



1.78 



12.24 



19.69 



2.84 



3 



1.67 



7.48 



46.63 



12.38 





3-73 



7.83 



24.8s 









3-43 



lO.II 



10.67 



4.01 



S-33 



5-91 



5-79 



37.62 

 12.98 



10.67 





2.56 





8.97 



2.66 



4 



1.28 



4.50 



7.46 



12.44 

 6.40 





2.07 



10.38 



9 25 



9.36 





1.82 



2.98 





4-94 





1. 81 



3.26 







WHEAT JOINT WORM'S 

 liarmoUta Iritici Fitch: Harmolita vaginicola Doane 



The joint worms, particularly the wheat joint worm, H. t r i t i c i 

 Fitch, have attracted little notice in recent years, though they occur 

 in most wheat fields and occasionally become very abundant, in 

 some instances causing nearly total destruction of the crop on 

 account of the plants being unable to produce normal heads or 

 because of the general breaking, lodging and consequent loss of the 

 crop. In many cases both exert an appreciable influence. 



The work of the wheat joint worm, H. tritici Fitch, is indi- 

 cated at thrashing time by the hard bits of straw containing larvae 

 which appear in the grain instead of being carried over into the 

 straw. An examination of such bits of straw, either in the field 

 or after thrashing, shows knots, swellings and twistings within 

 which may be found small, yellowish larvae about one-eighth of an 

 inch long when full grown. These abnormal growths interrupt the 

 flow of sap and as a consequence the afifected plants produce short 

 heads with comparatively few kernels and those developing are 

 apt to be small and more or less shrivelled. 



The wheat sheath worm, H. vaginicola Doane, has very 

 similar habits to the preceding except that the eggs are laid at the 

 base of the leaf sheath just above one of the joints and as a conse- 

 quence the walls of the infested sheath press upon the stem in such 

 a way as to prevent the sap flowing readily and the plants therefore 

 become stunted and produce only small, poorly developed heads or 

 none at all. Infestation by this species is indicated by a peculiar 



