44 
S. DEPARTMENT OF AGRICULTURE 
mental evidence obtained in Massachusetts during 1922 (Table 5). 
under conditions of. severe infestation, the ears (fig. 22) and stalks 
of the early-maturing or short-season varieties of dent corn are 
as susceptible to severe injury by P. nubilalis as the ordinary 
sweet or flint corn varieties. In general, however, the infestation 
Fig. 23. — Ears of sweet corn left to ripeu for seed, showing severe injury to grain 
and cob by European corn borer. Two cobs cut open to show borers within. 
Also note severe injury to ear stem. Medford, Mass., September, 1922 
and injury to dent corn, particularly the large-stalked and late- 
maturing varieties, has been less severe than to the earlier maturing 
and smaller-stalked varieties of flint corn. It is a matter of specu- 
lation whether this relative susceptibility and injury would be 
retained in regions where the duration of the growing season per- 
mitted the maturity of large dent corn varieties. Flint and sweet 
