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PROGRESS REPORT ON THE EUROPEAN CORN BORER 41 
EXTENT OF INJURY AND ECONOMIC LOSS 
CORN 
Most of the direct injury and loss to corn, as a result of European 
corn-borer attack, is caused by the larvae feeding on the grain and 
in the cob of the ear. (Fig. 21.) In addition to this direct loss 
to the ear there is also an indeterminate amount of indirect loss, as 
previously described. The injury to the lower stalks and ear stem, 
Fig. 21. — European corn-borer injury to grain and cob of 
flint field corn. Cobs sectioned to sbow borers witbin. 
One hundred per cent of the stalks and ears were in- 
fested and 17 per cent of the grain destroyed in the field 
from which tbese ears originated. Medford, Mass., 
October, 1922 
if severe and occurring before the ear is nearly mature, frequently 
results in a small or poorly formed ear. The actual extent of injury 
and economic loss resulting from the indirect injury to the ear and 
the stalk is difficult to estimate definitely, as it varies greatly in 
different fields and depends upon several factors, the most important 
of which are (1) percentage of plants infested, (2) the number of 
borers per plant, (3) the stage of development of the plant when 
attacked, (4) the part of the plant selected for attack, and (5) the 
