You can plant your corn in Iowa over a considerable period of time with reasonable assurance of maturing a crop. The planting time you choose may be expected to influence both yield and damage caused by the European corn borer.
Sprague, G. F.; Lilly, J. H.; and Rubis, David
"Can Planting Dates Beat Borers,"
Iowa Farm Science: Vol. 4
, Article 3.
Available at: https://lib.dr.iastate.edu/farmscience/vol4/iss10/3