Idaho’s congressional delegation is fighting a U.S. Department of Agriculture decision that prohibits poor women from buying potatoes with the money they get each month to buy nutritious food.

Lawmakers hope that they can change the farm bill as it works its way through Congress – it’s supposed to be finished this week.

The USDA decided late last year to prohibit potatoes in its Women, Infants and Children program, which is changing its guidelines to allow participants to buy more produce with their monthly stipends.

The WIC program gives poor women extra money, typically about $40 each month, to buy nutritious food while they’re pregnant, nursing or caring for infants. The program, which began in 1974, provides extra nutrition to an estimated 8 million people each year.

Most states give mothers vouchers to buy specific types of food designed to supplement their diets and their children’s diets. The USDA decided not to include potatoes, because a study found that many poor people already base their diet on them. The study, by the Institute of Medicine, looked at what sort of foods WIC participants were already eating and what sort of nutrients they were lacking.

Potatoes are the only vegetable not included on the USDA list, and Idaho’s potato growers are fighting the exclusion.