126 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
appropriation by the Ohio Legislature. Our field laboratory was 
located in Ashtabula County, northeastern Ohio, where the percent 
infestation was thought to be the highest in the state. In all our work 
we have been in constant touch with the State Department of Agri¬ 
culture, the Ohio Extension Service, and the Federal Bureau. Particu¬ 
larly does the Ohio Station Staff appreciate the generous cooperation of 
Mr. D. J. Caffrey and Mr. F. W. Poos. 
A part of our biological projects were necessarily limited because of 
the great difficulty in securing sufficient numbers of over-wintering 
larvae at the beginning of the season. Pupation began June 5 and 
ended August 7. The shortest pupal period was 6 days, the longest 
period 21 days; the average was 12 days. The season of maximum 
pupation was June 15 to June 20. From a small number of pupae and 
larvae found in the field on June 18, it is estimated that approximately 
26 percent had pupated under field conditions. This corresponds closely 
to the percent pupated in the insectary at the same date. 
Emergence of adults began June 20 and ended August 4. The period 
of maximum emergence was June 22 to June 28 with the peak of emerg¬ 
ence on June 27. It should be mentioned too that an empty pupa 
case thought to be Pyrausta nubilalis Hubn. was found in a stalk on 
June 18 in the same field that contained larvae of the corn borer. 
Female moths lived from 1 to 25 days, or an average of 14.3 days. 
The preoviposition period varied from 4 to 11 days, or an average of 7 
days. The incubation period ran from 5 to 8 days, or an average of 6 
days. The minimum number of eggs deposited by an individual was 
17 and the maximum 737—an average of 235. 
During the past season an attempt was made to ascertain the average 
percent infestation in the area that was first found infested and also to 
get all possible information relative to the clean up measures prosecuted 
in Ashtabula county last spring. Territory along the lake front and 
back not more than three miles was pretty thoroughly covered. The 
following table indicates the present infestation found in Lake and 
Ashtabula counties. It will be remembered that these two counties are 
adjacent and that Lake county had no clean up campaign. 
Table Showing Infestation in Ashtabula and Lake Counties 
County 
Fields exam 
Av. 
Max. 
Fields exam. 
Av. 
Max. 
Total av. 
Sweet corn 
inf. 
inf. 
Dent corn 
inf. 
inf. 
Ashtabula.. . 19 
.011 
.10 . 
. 16 
.012 
.05 
.0115 
Lake... 
.... 15 
.014 
.10 . 
. 21 
.013 
.075 
.0135 
It will be noted that the difference between the average totals of the 
