A heat dome will consume the Plains and Mississippi Valley into the South this week with "oppressive and dangerous conditions" expected at least through midweek, the National Weather Service reported early Monday.

"It’s starting to explode," one agronomist says. Corn growers in 13 states have confirmed tar spot outbreaks.

“I do think we’re going to see relief from the heat as we work into the weekend—the 70s or low 80s could creep into Iowa, Minnesota, Wisconsin and Northern Illinois,” says Bret Waltz, BAMWX meteorologist.

The licensing agreement comes after two years of the companies conducting independent field trials.