INSECT PEST SURVEY BULLETIN 
Vol, 21 Supplement to Number 6 August 15, 194l 
HESSIAN FLY SURVEY AT HARVESTTIME 1941 
Summarized, by W. B. Cartwright 
Division of Cereal and Forage Insect Investigations 
U. S. Bureau of Entomology and Plant Quarantine 
Pield surveys made by the Bureau of Entomology and Plant Quarantine 
laboratories at Manhattan, Kans., La Fayette, Ind., and Carlisle, Pa., and 
bj 7 - the State agricultural experiment stations of Illinois, Ohio, Kentucky, 
Missouri, and Nebraska indicate that Hessian fly infestations are low in 
wheatfields throughout eastern, north-central, and western Pennsylvania, 
eastern Maryland, Delaware, northwestern and northeastern Virginia, north- 
eastern Ohio, southwestern Michigan, northern Indiana, southwestern’ and 
south-central Nebraska, northwestern Kansas, and northern Oklahoma. There 
are, however, menacing populations of flies in local fields and areas in most 
of these regions. 
Hessian fly infestations range from low to moderate in south-central 
Pennsylvania, western Maryland, north-central North Carolina,, northwestern, 
east-central, and southeastern Missouri 5 moderate to heavy in southern Vir- 
ginia, western and central Ohio, southeastern Michigan, central and south- 
ern Indiana, eastern and southern Illinois, eastern Kentucky, west-central 
and eastern Tennessee, northeastern and -west-central Missouri, north-central 
and south-central Kansas; and heavy infestations in western Kentucky, south- 
western Missouri, southeastern Nebraska, northeastern and southeastern Kansas 
General examinations and observations by State entomologists in Iowa and Illi 
nois indicate that Hessian fly may be found moderately to fairly heavy in the 
counties where winter wheat is ; grow. in the States. Rigid observance of the 
safe-seeding dates is advised in the major winter Wheat Belt due to the wide 
spread and general increa.se of -the fly this year. 
The data summarized in the following table, and the accompanying map, 
indicate more fully the regions covered by the survey and the general trend 
of fly infestations. A field Sample in the survey usually consisted of 50 
wheat stems. 
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