Baltimore Gas and Electric Company will begin pursuing rate increases more "frequently and aggressively" to keep up with inflation, company chairman Bernard C. Trueschler told the company's stockholders today.

Trueschler said the utility is counting on a favorable rate decision by the Public Service Commission in June on $147 million in rate hikes it has requested to help improve its financial position.

"With inflation as devastating as it is, your company must seek rate increases frequently and aggressively," Trueschler told the stockholders. "Approximately half of our current $147 million request for base rate increases is needed simply to earn our authorized rate of return. . . ."

First-quarter earnings for the company, announced at the stockholders' meeting today, were down from the previous year. "We probably won't see a real improvement in our financial performance until the Public Service Commission renders what we hope will be a favorable decision," Truescher said.

Earnings for the first quarter were $23.8 million (75 cents a share) compared with $34.6 million (1.11) last year.

Earnings were depressed by "substantially higher" natural gas prices from the company's supplier and increased operating and maintenance costs, the company said in a statement. Those factors plus high interest rates "could result in the continuation of this adverse trend in financial performance" until the PSC decision, the company said.

The company also blamed "continuing conservation efforts by our customers and the effect of warmer weather on energy usage for house heating" for low electricity and gas sales.

Total electric sales for the last three months rose only "slightly," and gas sales increased 4.6 percent, the company said.

To help conserve oil, Trueschler said the company is exploring with Maryland and Baltimore county officials the possibility of burning trash to produce energy. "It looks like dirty, shredded paper and has about half the heating value of coal," the company chairman said.

In the area of nuclear safety, Trueschler said the company is implementing new safeguards at its Calvert Clifs nuclear plant to "assist the operators in quickly analyzing any incident in order to minimize its severity."

Costs of such improvements will exceed $60 million, Trueschler said. Another $10 million will be spent on a control room simulator at the plant for training plant workers.

At another local stockholders meeting, First Virginia Banks Inc. yesterday stressed the company's successful 1979 financial report and said the bank's level of loan losses was well below all of its major competitors.

Thomas K. Malone, the bank's chief executive, said that management of the bank's spread and "safety and liquidity" were the key points in First Virginia's continued growth.

In Richmond, First and Merchants Corp. announced the purchase of up to 150,000 shares of its own common stock, subject to regulatory approval.

The shares will be held as Treasury stock and used for employe benefit plans, merger possiblities and for other corporate activities, First and Merchants said.