our corn on corn had some of our best yields.have some ground that's been in continous corn for over 15 years.seems like if there is going to be a problem it will be first year corn on corn.starter seems to help with corn on corn,if we don't use starter i like to put down about 30-40 units of nitrogen preplant.i believe insecticide is a must,something that controls secondarys is almost more important than the rootworm control.it is a high managment environment,things like properly set row cleaners,proper down pressure on row units,good depth control,planting 2-3000 more seeds per acre in tough emergence situations.and like some of the other posters have posted.controlling traffic patterns,hybrid selection.which is a tough one because very few plots have any corn on corn data,and if they do it was probably raised the same as the the corn on soybeans,hence the usuall10-20%yield drag.