INSECT PEST SURVEY BULLETIN 
Vol. 20 
Supplement to Number 1 
March 15, 19^0 
ESTIMATES OF DAMAGE BY THE EUROPEAN CORN BORER IN 1939 
By A. M. Vance, Entomologist, 
Division of Cereal and Forage Insect Investigations, 
Bureau of Entomology and Plant Quarantine, 
United States Department of Agriculture. 
Gross estimates have been calculated of the amount of damage, j.n‘ dollars, 
caused to corn in 1939 the European corn borer (Pyra usta nub ilalis Hbn. ) over 
practically two-thirds of the area infested by the insect in the United States. 
Although these estimates are approximate, they present a fairly reliable picture 
of the current economic importance of the corn borer over a wide area of its dis- 
tribut ion. 
It is estimated that the European corn borer in 1939 caused a loss of almost 
$4,000,000 to the corn crop valued at approximately $106, 000,000, produced in 2S5 
counties in the Northeastern States, Based on less extensive data, the estimated 
loss to corn by the borer in 1938 was placed conservatively between 2 and 2-1- mil- 
lion dollars, 
ihe damage estimates in 1939 were calculated in the same way as in 1938~^and 
in- other previous years. The percentage of loss of yield was obtained by apply- 
ing established damage indices to the^data on countv abundance of the corn borer 
determined in the fall survey of 193 9 , Data, on corn production were taken from 
the 1935 Agricultural Census and seasonal market quotations on corn, contributed 
by the Agricultural Marketing Service of the United States Department of Agricul- 
ture in Washington and in the field, and by several State and city marketing 
agencies , 
In the calculations the following prices were utilized, the 1939 quotations 
for corn harvested for grain being preliminary and the prices of sweet corn be- 
ing averages 01 daily quotations for the crop marketing season. 
C pjrn , harv e_sted_ for grain, .cents per bus hel; - Maine-, New Hampshire, and Vir- 
ginia, 72* Vermont, Rhode Island, and Connecticut, 71 5 Massachusetts, 70; New 
S rk Au. * NCW Jerse ^’ Pennsylvania, 6H; Delaware and Maryland, 62; Michigan, 
54; Ohio 'and Wisconsin, 53; Indiana, 50. 
Swegt_g.qrn — c en t s_p er dozen ears: Connecticut, eastern New York, and north- 
eastern Pennsylvania, 17; Massachusetts, Vermont, New Hampshire, Maine, and Rhode 
island, 14; New Jersey, Delaware, Maryland, Virginia. Michigan, western New York, 
IT ~ ~ " — 
Insect Pest Survey Bui; v. 19, sup, to No. 8 , Oct. 20, 1939. 
“ See Inse ct Pest Survey Bui. v. 19 f sup. to No. 9, Dec. 15, 1939, 
-37- 
