News of the nation's 10.1 jobless rate was only an hour old when state legislator Norman Sisisky, a hard-running, big-spending Democratic candidate for Congress in southeastern Virginia, used the occasion for a broadside against Reaganomics.

"This recession is the direct result of the 'trickle down' policies of my Republican opponent," said Sisisky, a state delegate from Petersburg who is running against ten-year Rep. Robert W. (Bob) Daniel Jr. That was at a 10 a.m. press conference, staged in front of the local unemployment office.

Sisisky repeated the message later at a Firestone nylon factory in Hopewell where 500 workers -- 60 percent of the plant's employes -- will be laid off by the end of the month.

Reaganomics is the central theme of the Sisisky campaign, considered one of the Virginia Democrats' best shots at dislodging a Republican congressman this fall. Unemployment in Daniel's Fourth District -- which stretches from the port city of Portsmouth to the heart of conservative Southside -- is at a record post-World War II high: 12.4 percent in rural Suffolk and 9.1 here.

In a costly television campaign, Sisisky is telling voters that the district's jobless rate has jumped 52 percent since 1980. Like many other Virginia Democrats, he tiptoes around the question of President Reagan's intentions -- "The Republicans didn't mean to start a recession, but they did" -- but his verdict on the president's program is succinct. "Fiscal insanity," is the way the millionaire soft-drink bottler and beer distributor, son of Lithuanian Jewish immigrants, sums up supply-side economics.

"I'm worried, I really am," said 55-year-old Sisisky to a group here this week, "Businesses are failing at the highest rate since 1932 and farmers aren't in a recession, they're in a depression."

Daniel, 46, who served four years in the CIA before coming home to manage his 4,500-acre plantation on the James River, is a Reagan defender. As one of the most conservative members of Virginia's conservative delegation, Daniel argues that national economic policies are only catching up with his own consistent record of "pay-as-you go" fiscal restraint.

While he deplores the increase in unemployment, Daniel holds that Republicans were given the dirty work of cleaning up after the Democrats' legacy.

"Wherever I go, I ask people whether they want to go back to the conditions of two years ago -- 20 percent interest rates and 13 percent inflation -- and no one yet has said they wanted to," said Daniel. "At least, we've got some things turned around."

The battle between Daniel and Sisisky generally is believed the closest race the district has seen in decades. Even Watkins Abbitt, a Byrd Democrat who held the seat from 1948 to his retirement in 1972, can't recall one like it. "We've got two good men," said Abbitt, a former Democratic party state chairman who now lives outside the district and has stayed away from any endorsements, "So you see, that makes it a pretty tight race."

Incumbency is a powerful factor here: in Abbitt's words, people in the Fourth are "very loyal." But so, too, is the strength of the Democratic label: the Fourth bucked the tide in Virginia in 1980 and alone among the state's 10 congressional districts, voted for Jimmy Carter over Reagan. "The Fourth District is basically Democratic," said Abbitt. "For that reason, a Democrat would have strong support when he starts."

Sisisky's polls are showing the Democrat making "substantial" inroads into Daniel's lead, said campaign manager Tom King. And local Democratic leaders are hoping discontent with the economy will help them approximate the turnout in last year's gubernatorial election, when Democrat Charles S. Robb easily carried the district.

The core of the Democrats' strength is the district's 40 percent black population, a population that explains both why the Fourth elected Virginia's only black congressman at the end of the last century and why, in the '60s, it was a center of "massive resistance" to school integration.

This year, Sisisky, elected four times from Petersburg, is counting on a heavy media campaign to get across a message that the district -- with the lowest per capita income, the lowest educational levels, the most substandard housing and the second highest unemployment rate in the state -- needs a Democrat in Congress.

To make his point, Sisisky has hit hard at his opponent's voting record -- at his opposition to the extension of the Voting Rights Act and his vote against extending benefits for the unemployed. Daniel argues that the solution to the district's problem is less -- not more -- federal spending and links his opponent with the "O'Neill and Kennedy" school of liberalism.

Sisisky plans to spend at least $150,000 of his own money in a campaign that is expected to cost $400,000. That has raised charges from Republicans, who expect Daniel to spend half that amount, that Sisisky is trying to "buy the election." Sisisky has hired a professional campaign staff but more than half of his budget is earmarked for television, a costly proposition in a district that includes both the Norfolk and Richmond media markets.

Television costs, Sisisky says, are what have kept other Democrats from beating Daniel, who avoids the word Republican on ads and brochures. "This district is an incumbent's dream," said Sisisky, "Nobody has been able to communicate the message because he (Daniel) has been able to outspend them 2-to-1. That's why I've had to use my own money. We knew it was going to be very difficult to unseat a 10-year incumbent."

Sisisky, an exuberant man who built a fortune on his ability to sell Pepsi-Cola, is a natural campaigner. He has been at it 127 straight days and clocked more than 20,000 miles in the district, running through a schedule crammed with meet-the-candidate coffees, countless rural festivals and quick stops at shopping centers.

Virtually unknown outside the Petersburg area, Sisisky has already boosted his name identification with his telelevion ads. "So this is the famous TV personality," said one man at a gathering here. "I'll tell you, you've got some fantastic ads."

His style contrasts with the more introverted, scholarly Daniel, accused affectionately by one of his own supporters as "having no more personality than that little pen you've got there." Dressed in red-and-white striped shirt and grey suit pants, Daniel, 46, looked almost uncomfortable Thursday as supporters shepherded him through the crowds at a Harvest Feast in Suffolk's Peanut Park.

"I'm in the presence of friends," explained Daniel, shrugging off comments about his low-key style. "That's the way I am. I'm not loud and pushy." Rather, supporters say, his popularity is built on his diligence (he has a 98 percent attendance record), his constituent services and his membership on the Armed Services committee, considered important in an area heavily dependent on military spending.

Last week, Daniel accused his opponent of using "misleading generalizations" in an ad attacking his record on Social Security and at a press conference, chided Sisisky for campaign behavior "not in the tradition of decency of Virginia politics."

"To accuse me of acting in any way against the interests of the Social Security system is preposterous," said Daniel. But the Sisisky campaign, saying the ad is based on various Republican proposals approved during last year's budget fights, has refused to back off. "Those are facts," said a Sisisky aide.

According to Daniel, Sisisky has offended voters with his style. "I never saw so many astonished faces," said Daniel, describing the reaction of an audience to Sisisky's statement that he would vote against his "deeply-held beliefs" if that would help the district.

Sisisky argues that the district could benefit from a new approach. "If you believe one rigid philosophical viewpoint, adhered to without bending, is going to solve our problems, there's no sense in voting for me," he said.