Use lots of "Soy Soap" on yer corn.  I have a two year old supply at a steeply discounted price if you want some.  It's supposed to work wonders on everything you can plant. 

I highly reccomend you buy mine and give it a try.  There is only one stipulation to being able to purchase from me.  I get to deliver in a very dark parking lot deep in the inner city while wearing a ski mask!