PROGRESS EEPOET ON THE EUROPEAN CORN BORER 49 
An examination of Table 8 shows that in western New York the 
corn borer is now causing appreciable injury to all types of corn, and 
that while the present severity of the infestation is not comparable 
to that existing in New England, the degree of infestation is such 
that serious losses may develop in the near future, unless measures 
are taken to keep the insect in check. 
The comparative field counts of stalk infestation which were made 
in 1921 and 1922 in 8 fields, selected on the basis of personal 
judgment of average conditions, within the worst infested portion 
of the western New York area, showed that 26.2 per cent of the 
stalks were infested in 1921, with an average of 3.33 larvae per in- 
fested stalk (87.2 larvae per 100 stalks), while in 1922 in the same 
fields 18.9 per cent of the stalks were infested, with an average of 
1.76 larvae per infested stalk (33.3 larvae per 100 stalks.) Com- 
parable figures for the 1923 field survey show that in 30 fields, in the 
same area ivhere the 1921 and 1922 surveys were conducted, there 
were an average of 15.2 per cent of the stalks infested, containing 
an average of 1.3 larvae per infested stalk (19.8 larvae per 100 
stalks), while in 1924 there were an average of 27.8 per cent of 
the stalks infested, in 36 of the same or near-by fields surveyed in 
1923, containing an average of 2.7 larvae per infested stalk (75.1 
larvae per 100 stalks). Examinations for ear infestation in field 
and sweet corn in this area during 1923 showed that an average 
of 5.5 per cent of the ears were infested in 19 of the fields mentioned 
previously and also including sample examinations of the sweet- 
corn ears brought to two canning factories. A similar examination 
of the ears from the 36 fields surveyed in 1924, and from three 
canning factories, revealed that 9 per cent of the ears, on an average, 
contained the borer. Sample examinations of 2,700 sweet-corn ears 
delivered to a canning factory at Silver Creek, N. Y., during 1924 
revealed that 11.9 per cent of the ears examined contained the borer. 
The unusual abundance of the corn ear worm in both the eastern 
and western New York areas during 1921 rendered it difficult to 
obtain accurate records of grain injury which could be attributed 
solety to the corn borer. 
Ohio and Michigan 
In Ohio and Michigan there has been very little economic loss 
caused by the corn borer to the close of 1924. There was, however, a 
widespread dispersion of the pest in this area during 1924, accom- 
panied by an increase in intensity which amounted to 258 per cent 
when compared to conditions existing in 1923. Should the rate of 
annual increase which prevailed during 1923 and 1924 be continued, 
it appears reasonable to forecast that appreciable losses will become 
general in this area in the near future, especially since similar devel- 
opments in the older area of infestation across Lake Erie in Ontario 
have led to severe losses to all types of corn under similar cultural 
conditions to those prevailing in Ohio and Michigan. During 1923 
a survey of 133 fields of Ohio and Michigan revealed an average stalk 
infestation of 1.83 per cent, with an average of 1.41 larvae per 
infested stalk or 2.58 larvae per 100 stalks. These fields were selected 
throughout the area as representing average conditions according to 
the personal judgment of the field worker. A similar field survey in 
241 fields of this area during 1924 showed an average stalk infesta- 
25411°— 27 4 
