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State 
Nebraska 
Kansas 
Missouri 
Oklahoma 
Illinois 
Michigan 
Indiana 
Ohio 
Kentucky- 
Tennessee 
New York 
Pennsylvania 
Delaware 
Maryland 
Virginia 
Percentage 
of 
Percentage -.of 
infestation 
in 
infestation in 
1932 
1933 
25 
4 
21 
5 
27 
9 
4 
3 
29 
1 
19 
trace 
41 
1 
32 
1 
8 
2 
12 
4 
10 
3 
32 
3 
11 
trace 
21 
1 
11 
1 
EUROPEAN CORN BORER 2 
Despite the general decrease in the population of the European corn 
borer ( Pyrausta n ubilalis Hon.) in New York, many farmers complained of 
losses to early-planted sweet corn. The average plant infestation in 20 
fields in nine counties bordering Lakes Ontario and Erie was 35.6 percent, 
and the average infested plant contained approximately 1.5 borers. The loss 
in ears for the 20 fields amounted to approximately 28 percent. The adults 
deposited eggs in comparatively large numbers, resulting in a moderately 
severe infestation in the vicinity of Toledo. In the other Ohio counties, 
however, the corn was delayed by lack of moisture, and because of its small 
size during the oviposition period few eggs were deposited upon it. The ex- 
tremely warm, dry weather which prevailed throughout the oviposition period 
killed many eggs before they could hatch. Unfavorable conditions similar to 
those in Ohio prevailed over most of Michigan, although the sandy soil in 
that State absorbed the heavy spring rains more rapidly than did the Ohio 
soils, and it was possible to plant corn at the usual time. Extremely warm, 
dry weather, however, during the oviposition period killed many eggs. I 
fields examined were almost all late-planted and consequently were less 
heavily infested than the early-planted fields. Had it been possible to con- 
duct the Michigan survey two weeks earlier, it is quite probable that the 
1933 infestation survey data from that State would have been approximately 
equal to those of 1932, 
The following table gives the average numbers of borers per 100 plants 
for the nine-year period 1925-1933, based on examinations made in comparable 
counties: 
2 Division of Cereal and Eora-'o Insects, Bureau of Entomology, U. S. D 
