Republican Lt. Gov. John N. Dalton, attacking President Carter for the first time in his race for governor, today joined one of his running mates in attempting to make the proposed Panama Canal treaties a major issue in Virginia's Nov. 8 elections.

Citing the President's avowed friendship for Henry E. Howell, his Democratic opponent, Dalton charged that Carter was "trying to jeopardize Virginia's economy by giving away the Panama Canal."

In one of his strongest speeches in the current campaign, Dalton told the Virginia Conference on World Trade that ratification of the treaties would force up the prices of Virginia goods shipped through the canal. Any closing of the waterway, he said, would force massive layoffs in the state's ports.

Meanwhile, Republican lieutenant governor candidate A. Joe Cananda took his fight over the treaties to a Senate subcommittee on Capitol Hill. In what appeared to be an event staged as much for the media as for the senators - twice as many reporters as senators were present - Canada renewed his attack on the treaties.

Howell, who also spoke to the trade conference, said that the proposed canal treaties are a national issue and said Dalton did "a disservice to the people of Virginia" by trying to inject them into the race for governor. He said Dalton raised the issue because "he has taken a poll and (found) most Virginians" fear loss of American control over the canal.

"This is the way the Republican campaign has been structured: namely you find the fear of an individual and then you appeal to that fear in an effort to frighten you with respect to President Carter . . ." Howell said.

Dalton, who first expressed incredulity and personal opposition to the treaties when Canada first raised the canal issue in his race against Democrat Charles S. (Chuck) Robb, today spoke sternly and strongly about consequences of the treaties. He repeatedly called them "a vital issue." Dalton acknowledged at one point that as governor he would have no vote in the U.S. Senate, which must vote on the treaty.

That did not mean, he said, that a governor's opinion was without consequence in the Senate. "And, ladies and gentlemen, you better believe the governor of Virginia will have an impact on the ratification of this treaty."

Dalton based his charged that the treaties could jeopardize Virginia's economy on a belief that a canal closing would force Virginia manufacturers to ship their goods across the country to West Coast ports. This would boost transportation cost and force layoffs of Virginia poor workers. He also said that if the treaty is approved Panama is likely to increase ship tolls on the canal as much as 30 per cent over current rates, further adding to the cost of goods shipped from Virginia through the canal.

Although leaders of the conference, sponsored by the Virginia State Chamber of Commerce and some government agencies, said the 150 business people at the meeting were over-whelmingly for Dalton, both men received standing ovations when they arrived and left after separate, brief speeches. Dalton was interrupted by applause only once and Howell managed to provoke laughter repeatedly throughout his low-key appearance.

Not unexpectedly Dalton used his speech to portray Howell as a man "who has made a career of running down, whipping, badgering and otherwise humiliating the Virginia business community." Today, however, his language was stronger than before and included some new charges:

That Howell, in a 1972 Washington speech as Virginia lieutenant governor, "labeled every American businessman 'an embezzler' from the American consumer." Mounting the same platform a few minutes later, Howell flatly denied making the statement and cried aloud: "I'm saying, John, wherever you are, 'Tell the truth.'"

That Howell "has been on a union payroll for years." That charge is a reference to the retainers Howell's Norfolk law firm has received for representing labor unions. Howell has said his firm now represents three unions and that their retainers account for only a small portion of his firm's income. Dalton acknowledged to reporters that the fees may be small, but added "whatever you call them, he gets them regularly from labor unions."

At one point Dalton, in an unusual move, departed from his prepared text, to describe his remark as "harsher" than he has made before. Virginia's economy he said "faces two immediate threats: "one Howell and the other lives across the Potomac in Washington."

Dalton's harsh language about Carter came as something of a surprise. Republican strategists have acknowledged that Carter is more popular in Virginia today than he was at the time of his election when Virginia was the only Southern state he failed to carry.

A poll recently released here by a conservative group backing Dalton confirms that position. It describes Carter as "the most popular" political figure in a list that included Dalton, Howell, U.S. Sen. Harry F. Byrd Jr. and Republican Gov. Mills E. Godwin. The survey taken in early September and based on 810 telephone interviews, also showed that only 6.2 per cent of the Virginia electroate viewed the Panama Canal issue as "the single most important issue" facing the country. Those who believed the canal was an important issue tended to be "aminly ideological liberals" and not conservatives, the report said.