The Alexandria Dukes will be no more at the end of the baseball season.

Team owner A. Eugene Thomas said yesterday that he will move the Class A baseball team to Prince William County next year where they will play the 1984 season in a new $1 million stadium currently under construction in Woodbridge.

Thomas said the team may also get a new name--The Prince William Pirates.

Meanwhile, in Alexandria, City Council member Donald C. Casey Jr., who had fought to keep the team in town, said he was saddened by the loss, but not surprised.

"They needed an adequate playing facility to make it financially, and the city was not willing to help them," he said. "They had to leave."

Prince William is not only offering a better stadium, Casey noted, but it will also allow for the sale of beer, which was illegal in the Alexandria ballpark because it is owned by the Alexandria School Board.

Owner Thomas, who has long complained that the Dukes' current playing field, Four Mile Run Park, lacks adequate parking and seating capacity, began looking for another site for the team after the Alexandria City Council voted last month, despite Casey's efforts, not to build a new ballpark for the team.

The new Prince William facility, Davis Ford Park, is on Davis Ford Road just over the Fairfax County line. It is owned by the county park authority and was under construction before the Dukes expressed interest in moving. The stadium seats 5,780 spectators, 2,000 of them under cover between first and third base, and parking for 2,400 cars.

Additionally, the stadium will have eight 90-foot high concrete lighting towers, administrative offices, locker rooms and tunnels from the locker rooms to the dugouts. Thomas said Miller Beer has agreed to donate a $175,000 electronic scoreboard capable of flashing messages.

Under terms of a lease with the park authority, the county will maintain the field, and the Dukes will pay an annual rent of $3,000 plus a 10-cent-a-head fee for every additional spectator once the season's attendance reaches 45,000 and 20 cents per person once it reaches 100,000. Moreover, the park authority will get 5 percent of all concession revenues--including beer sales.

When the Dukes are not scheduled for the new stadium, it will be available for high school games and for use by other amateur baseball leagues.

The Dukes, a farm team of the Pittsburgh Pirates, have played at Four Mile Run Park since the team was founded in 1978.

Alexandria City Council member Patricia S. Ticer said that "it wasn't in the cards" for the Dukes to stay in Alexandria, where both land and money for baseball stadiums is scarce. But former mayor and potato chip czar Frank Mann, who helped bring the Dukes to Alexandria, criticized the city for spending its money on things like the Torpedo Factory Art Center instead of baseball.

"The Torpedo Factory, that houses artists, I think is fine. But it just occurs to me that if I like baseball I would like to think that it should get the same kind of attention," Mann said.

"I worked hard to bring that team to the city. To see it go is a very bitter pill to swallow. I wish them luck," Mann said.