The national average on-highway diesel price has reached $6.38 per gallon, and farm diesel in the heart of the Corn Belt climbed to nearly $6 per gallon — the backdrop for an Oct. 1 letter in which American Farm Bureau Federation President Zippy Duvall asked President Trump to suspend the federal highway diesel tax and waive penalties for emergency on-road use of dyed diesel.

The federal highway diesel tax currently runs more than 24 cents per gallon, a direct levy Duvall wants lifted temporarily while farmers absorb record-high fuel bills during harvest.

"Higher diesel expenses are hitting farmers at one of the most fuel-intensive times of the year – harvest," Duvall wrote. "Diesel is essential for the American economy and for farmers. Everything on the farm, from running tractors, combines and irrigation equipment to transporting crops, livestock and inputs, requires diesel. Farmers and ranchers cannot postpone harvest or simply stop using diesel when prices rise."

The second request targets enforcement rules. Dyed diesel — the red-marked fuel typically used in agricultural equipment and other off-road machinery — is often exempt from taxes or taxed at a lower rate than regular diesel, but its use on highways is generally restricted. The Farm Bureau asked the administration to waive federal penalties for emergency on-road use of the fuel, mirroring steps already taken in at least 10 states.

That state-level list is growing. Alabama, Arkansas, Georgia, Indiana, Louisiana, Missouri, Nebraska, North Carolina, North Dakota, Oklahoma, South Dakota and Texas have all moved to expand allowable uses of dyed diesel or provide other price relief for a defined period. Their tools vary: temporarily suspending penalties for on-road use or mixing of dyed diesel, increasing weight restrictions on haulers, suspending the fuel excise tax rate, or offering refunds on taxes paid for diesel.

For growers, the stakes land squarely on operating margins. Harvest is the most fuel-intensive stretch of the production calendar, and diesel prices feed directly into the cost of running combines, tractors and irrigation engines as well as trucking crops, livestock and inputs to market. Unlike discretionary purchases, fuel consumption at harvest cannot be deferred until prices retreat — which is why the Farm Bureau is pressing for relief tied specifically to the fall harvest window rather than open-ended support.

The organization has also published a Farm Bureau Intel analysis on the impact of diesel prices during harvest, underscoring the scale of the cost pressure behind the letter.

With the request now before the White House, the question for farmers heading deeper into harvest is whether federal relief — a tax suspension of just over 24 cents per gallon and penalty waivers for dyed diesel — arrives before the combines finish rolling.