I don't think that's the case when we have a wet May, though. There's also advantage in weed control with early season shading. And if there's hail, the corn leafs back out and canopies more quickly. Late in the season, corn plants in narrow rows may not lodge as badly, either. Other crops like soybeans and grain sorghum probably have a yield advantage with narrow rows.
Drawbacks There are a few drawbacks to narrow-row corn.
Bean says it's more difficult to scout because people can't walk through it as easily. Also, leaf diseases may be worse because of higher humidity. And spider mites tend to be a little worse. They also plant grain sorghum and a few soybeans on narrow rows. Their main reason for doing this is water conservation.