INSECT- "PEST SUE VJE. Y -ru LLETIH 
Vol. 17 • Supplement to Number 7 * September 15, 1937 
Hessian Fly Survey, Harvest-time 1937 
United States Bureau o'f Entomology and Plant Quarantine 
Cooperating with State entomologists' 
As shown on the accompanying map, this survey covers the main winter- 
wheat region of central and eastern United States. Throughout most of this 
area the hessian fly is now about as scarce as it ever becomes. Weather 
conditions more or less unfavorable to its activity last'- fall and again last 
spring, combined with generally delayed sowing of wheat last fall, have re- 
duced fly populations much below the threatening numbers prevailing in the 
central part of the winter-wheat b.elt a year ago. 
In Nebraska, Kansas, and Oklahoma infestations at harvest time were 
extremely light and practically no .material damage occurred or is likely to 
occur this year. Hessian fly populations are also generally low in Iowa, 
Missouri, northern Illinois, central and northeastern Indiana, Ohio, 
Kentucky, Tennessee, western and central Pennsylvania, Maryland, lelaware, 
Virginia, and North Carolina. In these States, however, occasional fields 
or localities now contain enough infestation to "be a possible source of 
local trouble next fall. A notable feature this year is the, unusual abun- 
dance of the- fly in some northern districts, including northeastern Iowa, 
southern Wisconsin, and south-central- Michigan. Qther regions containing 
moderate- to- severe infe.station, in which there is real danger, of an out- 
break next fall if weather -should favor fly activity, are southern Illinois, 
northwestern and southern Indiana, and. southeastern Pennsylvania. The 
farmers in all these districts should be warned of this danger and advised 
to observe the safe-sowing dates. 
This report is based on the following summarized data, and additional 
information received from State and Federal entomologists of Iowa and Wiscon- 
sin. The field samples used were mostly 50 stems taken on a short circuit 
into one side of the field. 
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LIBRARY ^ 
STATE PLANT BOARD 
