Financially outgunned in the Virginia governor’s race GOP primary, Corey Stewart is trying to blow a hole in the conventional political wisdom that winning comes down to who racks up the biggest war chest.

The self-described Trump acolyte has been trying to make the most of his cash-strapped situation by turning to the Trump playbook, harnessing social media and harping on issues such as immigration that get the Republican base going.

On Wednesday he made the trek across the Potomac with a staffer and streamed through Facebook Live an attack againstEd Gillespie, the GOP front-runner, accusing him of being beholden to large corporations trying to undercut Americans with a stream of foreign workers.

“He was the lobbyist on record for Tyson Foods when they smuggled in thousands of illegal aliens, taking American jobs and then, of course, exploiting these people — you know, paying them next to nothing when they got here and making them work in inhumane conditions,” Mr. Stewart said into a handheld camera phone. “Not to mention the fact that the biggest victims here are those who are victims of crimes committed by illegal immigrants.”

Mr. Gillespie’s campaign dismissed the attack as part of “a constant stream of fabrication and falsehoods” from Mr. Stewart.

Immigration has long been a thorny issue for Republicans — a potentially powerful cudgel, as then-candidate Donald Trump proved in last year’s elections, but one that also invites charges of racism.

It’s not the only area where Mr. Stewart, the chairman of the Prince William County Board of Supervisors, is following Mr. Trump’s campaign playbook. He’s also trying to create the kind of online presence that made Mr. Trump the talk of the campaign in 2015, long before the first GOP primary.

“I think that social media has transformed so many industries, but especially politics,” Mr. Stewart said Wednesday after he launched his Facebook Live attack at Mr. Gillespie. “You don’t need $3 million to $3.8 million that Ed has raised in order to win a primary for [a] governor’s race anymore.”

Mr. Stewart, 48, has remained loyal to Mr. Trump since getting fired as chairman of Mr. Trump’s Virginia campaign over a dustup with the Republican National Committee. He signaled Wednesday he hopes to recreate some of the social media magic that helped Mr. Trump win the 2016 election.

But, unlike Mr. Trump, Mr. Stewart has consistently trailed in the polls and on the fundraising front.

Mr. Gillespie, who served as a top adviser to President George W. Bush, has raised about $3 million more than Mr. Stewart, according to the Virginia Public Access Project, and leads him by 20 percentage points in a Washington Post-Schar School poll released this month. Also in the GOP race is state Sen. Frank Wagner.

Searching for ways to make up ground, Mr. Stewart has turned in part to first-person riffs on social media that have been viewed by tens of thousands and feature him, among other things, knocking “Establishment Ed” for not taking a firmer stand against Democratic Gov. Terry McAuliffe on illegal immigration and against Democrats who want to tear down the state’s Confederate memorials.

Mr. Stewart isn’t the political neophyte Mr. Trump was when entering the GOP presidential primary — though he has run statewide, losing his 2013 bid for the GOP nomination for lieutenant governor.

Mr. Gillespie, meanwhile, ran a closer-than-expected battle to unseat U.S. Sen. Mark Warner, a Democrat, in 2014.

Mark Rozell, dean of the Schar School of Policy and Government at George Mason University, said Mr. Stewart’s strategy suggests he knows how difficult his path to the nomination is.

“He’s trying to activate a base that is not terribly large using overheated rhetoric, divisive issues and wrapping himself in the Confederate flag,” Mr. Rozell said. “The latest statewide poll has Gillespie way up over Stewart right now. So Stewart has to count on most of his base showing up and most of Gillespie’s supporters sitting out the primary. Very, very long shot strategy.”

This week’s immigration attack stems from a report in The Washington Post highlighting the work Mr. Gillespie’s firm, Quinn Gillespie and Associates, which he co-founded with a Democrat in 2000 and left in 2007, did on behalf of Tyson Foods after the chicken processing giant was prosecuted for hiring illegal immigrants.

Mr. Stewart’s Facebook post read: “LIVE! From Quinn-Gillespie lobbyists in DC to discuss the Washington Post’s bombshell article about Ed’s complicity in Human Trafficking.”

A jury acquitted Tyson Foods of the charges in 2003, and Abbi Sigler, a spokeswoman for Mr. Gillespie, said her boss wasn’t involved in the matter anyway.

“Tyson Foods retained Quinn Gillespie in 2001 to provide public relations services dealing with charges for which a jury later found the company not guilty,” Ms. Sigler said. “As The Washington Post reported, Tyson’s made clear the firm was not retained to lobby on the issue and Ed was not involved in the day-to-day work for them.”

Mr. Gillespie has promised to stiffen immigration enforcement in Virginia, including encouraging state and local police to sign up to help federal officials and cracking down on so-called “sanctuary cities” that try to thwart enforcement.