Here is a good article to help determine if the disease you are seeing in the corn field is Northern Leaf Blight or Goss Wilt.
Corn-Diagnostics Goss Wilt vs Northern Leaf Blight-Quick-Guide[1]
Here is a good article to help determine if the disease you are seeing in the corn field is Northern Leaf Blight or Goss Wilt.
Corn-Diagnostics Goss Wilt vs Northern Leaf Blight-Quick-Guide[1]