54 REPORT OF THE STATE ENTOMOLOGIST 1 92 1 



Comparison of average percentages of infestation by Hessian fly 



Counly 



Albany 



Cayuga 



Chautauqua 

 Clinton 

 Columbia. . . 

 Cortland . . . 

 Dutchess . . . 



Erie 



Genesee .... 

 Livingston . . . 



Monroe 



Niagara. 

 Onondaga. . 

 Ontario. . . . 



Orange 



Orleans ...... 



Rensselaer . . 

 Seneca 

 Tompkins . . . 



Ulster 



Wayne 



Wyoming — 

 Yates 



1917 



1918 



1919 



1920 

 6.12 



1921 





1. os 



9-39 



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 



15-77 



29.82 



761 





1. 19 



591 



16.37 



4-29 



4 



1.78 



12.24 



19.69 



2.84 



2 



I.67 



7.48 



46.63 



12.38 





3-73 



7-83 



24-85 









3-43 



10. II 



10.67 



4.01 



5-33 



5-91 



5-79 



37-62 

 12.98 



IO.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 WORMS 

 Harmolita tritici Fitch : Harmolita vaginicola Doane 



The joint worms, particularly the wheat joint worm, H. tritici 

 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 w r orm, 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 affected 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 



