There has been questions about the effect on corn with high heat indexes. I checked one field, that by the way just started to show some tassels on 7/19.
 On 7/16 ( 1st picture ) the corn was 62 inches tall and had 11 collars, and on 7/19 was 76 inches tall had 13 collars(2nd pic).

(antelope nw nbc corn 7 16 2011 001.jpg)

(antelope nw nbc Bt corn 7 19 2011 001.jpg)

antelope nw nbc corn 7 16 2011 001.jpg (56KB - 53 downloads)

antelope nw nbc Bt corn 7 19 2011 001.jpg (59KB - 52 downloads)