The Rossmoor Corp., an adult community development firm based in Laguna Hills, Calif., recently announced in its annual report that it might liquidate itself because "current economic conditions greatly limit the potential for profitable investment in the real estate development field."

However, Rossmoor Construction Corp., the Rossmoor spinoff firm developing the Rossmoor adult community near Norbeck, will apparently continue building co-op and condominium apartments there.

Albert Ceresa, president of both Rossmoor Corp. and the construction firm, said that the latter was "spun off from Rossmoor Corp. several years ago" and is operated independently. Ross W. Cortese, founder of the Rossmoor concept of "Leisure World" communities for persons over 50, is chairman and chief executive officer of both corporations.

The ammouncement was contained in the publicly held company's annual report, which said that "record-high interest rates, very high and rising land and construction costs, and increasing difficulties and delays in obtaining government approvals" were diminishing residential development opportunities.

Ceresa was in Washington recently to meet with Lewis Letson, executive vice president of the construction firm. Ceresa said that Rossmoor has been looking unsuccessfully for a new community site in California, where it has nearly completed its 13,00-unit Laguna Hills community south of Los Angeles.

Ceresa and Letson insisted that the local corporation intends to complete the 900-acre Rossmoor Maryland community in about eight years. It has 3,700 residents and 2,600 completed units. The community has land for an additional 2,000 apartments. Earlier construction efforts there were concentrated on town houses and one-story houses. The shift to apartments was made several years ago to "keep prices from going out of sight," Letson said. New Rossmoor apartments are priced from $57,000 to $77,000.

Marika Sumichrast, head of marketing at the local Rossmoor, said that 129 net sales were made in 1979. She said a small condo apartment building is under construction and that a new co-op apartment building will be started soon.