Diesel prices are at record highs just as many U.S. farmers need fuel for combines, tractors and other equipment.

They are harvesting soybeans and corn, two of the nation's largest crops.

The spike adds to an already tough year, with higher costs for fertilizer, seeds and equipment.

Diesel hit a record U.S. price on Sept. 4, averaging $5.85 a gallon for the first time.

The six-month war with Iran had disrupted the world's flow of fuel.

By Friday, the average had risen to $6.05 a gallon, according to AAA.

Prices are now 60% higher than before the U.S. and Israel launched the war in late February.

At that time, the average was about $3.76.

Paul Mitchell, a professor at the University of Wisconsin-Madison, said the prices hurt.

He said the cost affects not just harvesting but also hauling grain and silage.

This includes moving crops from fields to farms and then to buyers.

Jason Kurtz, a corn and soybean farmer near Forest City, Missouri, said he was paying twice as much for diesel this year.

His combine uses 200 gallons a day, and he expected to run it for 30 days.

Kurtz, 49, said he still had to run the machines and use the diesel, so it cuts into his bottom line.

He said his finances were already tight after paying more for fertilizer and chemicals.

Kurtz, who voted for President Donald Trump, said he planned to delay some farm work.

He hoped diesel prices would fall.

Mitchell said cash-strapped farms are struggling most to decide what to cut.