Donald Trump looks set to alienate the farmer vote in the upcoming US presidential election with his stance on immigration reform.

US farmers depend on seasonal workers from outside of the US, but Trump wants to deport undocumented immigrants, many of whom make up the workforce of farms in the south of the US.

The core principle of Donald Trump’s immigration reform is to “build a wall across the southern border” (of the US).

However, US farmers say that Americans won’t do the back-breaking farm work that workers from across the border will do.

Chuck Conner, President of the National Council of Farm Co-operatives, told the website Politico that roughly 1.4m undocumented immigrants work on US farms each year, or about 60% of the agricultural labor force.

The American Farm Bureau Federation last year released a study that found that if an enforcement-only immigration bill was passed by Congress fruit production in the US would drop by as much as 61%, food prices in supermarkets would rise by 6% and the average net farm income would drop by as much as 30% – due to a lack of labour.

One US farmer said Trump poses a serious threat to US farmers struggling to get their crops to market.

Frank Muller, who grows tomatoes, peppers, almonds and walnuts on his California farm, told Politico that he would be forced to shut down if migrant workers were not available.

“My farm would shut down today if you removed my workforce. You hear all these disparaging remarks about immigrants, but these guys are the hardest-working, most dedicated people I’ve ever seen in my life,” he said.