That's a good question. I don't really know.

The main thing my customers tell me is to use sa good resistant variety and change seed genetics every year.

However my seed supplier this year said to stay (2nd year) with the same RU-VT3 genetic variety so we'll see. Expensive but it has worked so far.

I think the fact corn is on 30" rows and moved back and forth 15" every year compared to wheat which is much thicker and in the same spot every year is one reason for the difference. 

There is just much more air between the rows.  Maybe others who have been continuous corn can add a comment.

Jim at Dawn