Driving through the state this fall you wouldn't get the impression that the corn borer was putting Iowa out of the tall corn business. We've had two record crops in Iowa since the corn borer first appeared in 1942. Even though corn borers had spread through every county in the state by 1948, the damage wasn't crippling. The answer is that we've been able to control the borer fairly well.
"Corn Borers on the March,"
Iowa Farm Science: Vol. 3
, Article 5.
Available at: https://lib.dr.iastate.edu/farmscience/vol3/iss8/5