Table 2. Accumulated degree-days (developmental threshold of 50 deg F) from
initial capture of moths in the spring to first occurrence of life stage or
activity of first-generation European corn borers. (From European corn borer:
Ecology and Management,
NCR Publication No. 327, Iowa State University, Ames.)

a Average number of days of development to reach the first occurrence
of the stage or event since initiation of the previous stage listed. For example,
it takes about 16 days from first moth capture to egg hatch; first instars require
about 6.6 days to develop to second instars; etc. The number of days varies if
temperatures are cooler or warmer than average.