LOS ANGELES – For the recovery to gain steam, most economists believe small businesses need to be strong enough to hire new workers. But according to one measure, the employment picture in this sector is weakening.

Intuit Inc., which provides payroll services for small employers, says the nation’s tiniest companies had fewer new hires last month than any time since October.

The data are further evidence of a trend that has had many economists worried for months and intensifies concerns that smaller firms may not be robust enough to help lead the country out of its financial slump.

The slowdown in hiring is particularly troublesome, experts say, because small businesses typically hire first during a recovery.

A reluctance by little companies to add positions could mean that the big firms, which typically lag behind, will add jobs even more gradually.

“It’s a bad sign,” said Susan Woodward, an economist who tracks small business employment for Intuit. “Small businesses hire first — and they’re losing their steam.”

To calculate its estimate of national hiring, Intuit uses payroll information from its 56,000 small-business customers. The company defines small businesses as those with fewer than 20 employees.

Intuit’s data show that small businesses hired just 18,000 additional workers last month. That’s still positive territory, but it’s less than a third of the 60,000 that were added in February, when it seemed that an employment recovery was imminent. Additional hiring dropped steadily during the spring, to 40,000 in April and 32,000 in May.

“It’s disappointing,” Woodward said. “Considering how many unemployed people there are, it’s disheartening.”

Business owners say they’ve ridden a roller coaster over the last several months, cheering when good times seemed to be back — only to be disappointed as customers backed away again this spring. Many had planned to hire new people but pulled back in recent weeks.