John Dalton wound up his Northern Virginia campaign, for the governorship yesterday by calling on his Democratic oppontent, Henry E. Howell, to disavow publicly a wodely circulated promise to seek the repeal of the state sales tax on food and clothing.

The Republican candidate issued his call in speeches to separate crowds of more than 300 persons at the Keena Shrine Temple near Fairfax and at the Franconia Fire House.

Interviewed while campaigning in Southwest Virginia, yesterday, Howell said the letter was sent by an avid supporter of t his from Falls Church, Boyd Hogge, who sends out letters on its own. "Boyd doesn't take advice," Howell said, "he does what he thinks is right," Howell said that removing the tax on food was a "goal", but not something he has said he can accomplish in the first years of his administration.

"My opponent owes the people an explanation and public disavowal of this letter," Dalton said, "just as I called a press conference to disavow television advertisements planned by an independent group that erroneously state some of my opponent's positions."

Earlier in the campaign, a group of conservatives called Independent Virginians for Responsible Government abandoned an anti-Howell television campaign after Dalton found fault with the ads and called publicly on the IVRG to channel its efforts through the Dalton canmpaign.

Howell campaign manager William Rosential said the campaign did not authorize the letter and does not know how many were mailed.

The letter was mailed under a Howell campaign bulk mail permit. A Dalton campaign spokeman said the postal service confirmed that between 150,000 and 200,00 pieces of mail have been under that permit in recent days. A Dalton campaign official also said that the type of mechanicl addressing machines used on the senior citizens letter is noemally used for mailings of more than 20,000 or 30,000 letters.

Howell campaign manager William Rosenthal said the letter was mailed by Howell supporter Boyd Hogge of Falls Church. Rosenthal said the campaign did not authorize the letter and does not know how many were mailed.

Both candidates were scouring the hills and hollows of Southwest Virginia for votes yesterday, navigating the narrow mountain roads in the course of a blitz of separate rallies.

The efforts were concentrated here today, partly because of the fiercely partisans feelings that motivates voters here, and partly because the Ninth District is condidered crucial for either candidate's victory on Tuesday.

Dalton's home is in the Ninth District, but Howell carried it in his race against Governor Mills E. Godwin in 1973.

The Democratic rallies tended to be somewhat casual, but the feelings were intense and they were well attended despite flash floods having washed out several roads. Babies toddled on the stage while speaker talked, visiting reporters were greeted with applauses, and people in the audience talked back affectionately to speakers on the stage.

At one point in lengthy introductuon preceding Howell's speech in Grundy, a 5-year-old boy wearing a Democrat inspired styofeam boster was produced from the audience and placed on stage. He was given a microphone and announced in firm tones: "Love the Lord, hate the Devil, and vote Democratic."