Joshua Dirks began last Thursday in Tulsa, Okla., as a lighting technician on Kiss’s arena tour. He ended the day on a bus home to Nashville as that tour — along with the rest of the multibillion-dollar concert industry — came to an abrupt halt.

Last week, Live Nation Entertainment and AEG Presents, the two biggest powers in the industry, put their shows on hiatus amid growing concern over the rapid spread of the coronavirus, sending stars like Billie Eilish, Jason Aldean and Cher to social media to apologize to their fans for the scuttled shows.

Behind the artists who appear onstage, however, is a fragile pool of thousands of workers like Mr. Dirks, who perform much of the labor that allows tours to go on — from sound and lighting to transportation, merchandise sales and hospitality. Most are freelancers with few if any employment protections, and they now face months of uncertainty, and potential economic ruin, if the touring interruption consumes the all-important summer season.

“The next half of my year,” Mr. Dirks said, “is floating somewhere in limbo.”

Little seen by the public, the crews that go on tour with artists are mostly not unionized, and bounce from job to job with often little more than a few months’ notice. For years, as the touring business grew and ticket prices swelled, there has been plenty of work. The top 100 tours in North America had $5.6 billion in ticket sales last year, more than double the $2.4 billion in 2009, according to Pollstar, an industry trade publication.