Conjunto music has been very good to Hector Barron.

Barron is the founder and leader of Los Fantasmas del Valle (roughly “the ghosts of the valley”), a much-revered conjunto group from Texas that will be playing at the 66th National Folk Festival.

The group has been in existence since 1968. Barron, 60, on bass and Julian Figueroa, 58, on bajo sexto (a 12-string guitarlike instrument) and vocals have been with the band since the beginning. Drummer Cruz Gonzalez, 58, joined eight years ago. The youngster of the group, 20-year-old Rodney Rodriguez, came on board four years ago, replacing longtime accordionist Mike Gonzalez, who left for health reasons.

“We pretty much joined for life,” Barron explained in a phone interview from his southern Texas home. “We like what we’re doing. People like our music. We’re working more than ever right now. That’s what keeps us going.”

Conjunto (kohn-HOON-toh) is a form of musica tejano. The style developed in the late 19th century, when immigrants from Central Europe brought the button accordion to Mexican working-class communities in south Texas. The accordion, traditional Mexican genres and European dances such as the polka, mazurka and waltz melded into a new musical form. A lively music primarily for dancing, conjunto (which means “group”) centers on the accordion and bajo sexto, with drums and bass a later addition to the mix.

Los Fantasmas del Valle got its start in Mercedes, Texas, a city in the Lower Rio Grande Valley. The region, called “El Valle” by local residents, is a hotbed of conjunto music. The group’s name was inspired by its first recorded song, “Mis Pasos Andaran,” about a young man whose ghost still haunts his lover.

The band has made more than 40 recordings in its career. It was honored as Conjunto of the Year in 2002.

“Conjunto players are mostly Mexican Americans, who mostly work in the fields, then play on the weekends,” Barron said. “That’s how most of us got into it, by necessity. We’ve been pretty lucky, to make a good living at it.”

Rodriguez was familiar with the group and didn’t have much trepidation about joining.

“When they called me and asked me to join, I said yes,” he recalled in a phone interview. “I practiced to a cassette at first, because they wanted the same style [as Gonzalez, the previous accordionist]. I tried to imitate him as best I could. With practice, I got the hang of it.”

The group’s other three members have been together for quite a while. Rodriguez is willing to make a similar commitment.

“I like it a lot, so I think I would stay,” he said. “I want to get some school, too, because you never know. But they’ve been together for 40 years, and I’m pretty proud to be part of the group.”

Barron estimated that 95 percent of what his group plays in concert are its own originals.

“We mix our music up with different tempos, playing rancheras, boleros and cumbias,” he added.

Barron said his band rarely leaves its home state these days.

“We used to tour all over the United States, out of necessity,” he said. “Now we get lots of work in Texas.”

Their festival appearance marks Los Fantasmas del Valle’s first trip to Maine, but their second time at the National Folk Festival. They previously played at the festival in 2001 when it was held in East Lansing, Mich. It’s an atmosphere that Barron enjoys.

“We loved it,” he said. “We like to see the different kinds of music. Everybody there understands music.”