Owners of the New York Apples and Boston Lobsters, until recently considered two of the strongest franchises in World Team Tennis, confirmed yesterday that they will not operate teams in 1979. Their decision reinforced widespread speculation that the league will disband before the scheduled start of its sixth season next spring.

Earl (Butch) Buchhols Jr., commissioner of the league that has operated in the red since its inception in 1974, answered queries about WTT's future with a prepared statement: "Discussions are continuing amongst the franchises in an attempt to reach a final resolution. At such time as a resolution is reached, World Team Tennis will have a statement."

Plans for a seven-week, $1 million women's tournament circuit in Europe during May and June pose a particular threat. In the absence of such male stars as Bjorn Borg, Jimmy Connors and Guillermo Vilas, WTT replied heavily this year on the drawing power of its leading women players, including Wimbledon champ Martina Navratilova and U.S. Open titlist Chris Evert.

Sol Berg, owner of the New York team that won the WTT championship in 1976 and 1977, issued a statement saying, "Due to a lack of commitment at this time from major players . . . for the 1979 season, the Apples have no alternative but to suspend operations."

Robert Kraft, president of the Lobsters, who were runners-up to the Los Angeles Strings for the league title this year, said he would decide by Oct. 1, 1979 whether his team would return in 1980 if the league survives.