Striking independent truckers maintained blockades at several major diesel fuel depots along the mid-Atlantic corridor yesterday in a pincer-like action that cause more, but still not widespread, shortages at wholesale and retail businesses in the Washington area.

According to distributors and merchants surveyed in the region from Baltimore to Richmond, the 18-day-old strike by the nation's 100,000 independent truckers has yet to result in serious shortages of basic goods, but may do so if the protest continues much longer.

Although wholesalers reported that some food products - cheese from Wisconsin, shortening from Tennessee and shrimp from Florida - were in short supply, the major food chains in the area said their shelves were still adequately stocked.

"Shipments are coming in a day or two late, but right now we really don't think it's that bad," said John DeMoss of the Virginia Food Dealers Association. "There is no need for any consumer to do any hoarding."

The most pressing food distribution problem in the area was reported on Virginia's Eastern Shore, where farmers claimed that their potato, string bean and cucumber crops would soon rot if they were not moved to market. "It looks very bad," said Preston Kellam, a farmer on the shore. "It looks like we're in for a bloodbath."

The vegetable wholesalers in the region also reported problems resulting from the truckers' strike. Lew Weinstein, an official at the Maryland Wholesale Produce Market in Jessup, said his company is getting just seven of the 20 scheduled truckloads of fruits and vegetables a day. On the Virginia side, Mark Lewis, a vice president at Green 'N Things produce company in Alexandria, said his deliveries were delayed by three and four days.

And, added Lewis: "The growers in California have already warned me that if the strike continues, it may become impossible to find trucks in which to ship the goods."

Food merchants and restaurant operators throughtout the region said that suppliers warned them over the weekend that the worst may be yet to come. "I didn't have any trouble when I sent my order in on Friday," said Hunter Smiley, manager of the Top of the Town restaurant in Arlington, "but the Armour Meat Company told me that I was lucky I called in then. They expect problems if this goes on for another week."

Similar reports came from managers of department stores, shoe stores, furniture stores and florist shops.

While the truckers' strike presented these merchants with the mere threat of a shortage, the protest has already struck hard at the moving industry in the area. The manager of Smyth Van & Storage in Alexandria, for example, said that his business is at a standstill. He said the company's three trucks were grounded and that he was making no long distance hauls because "I don't want to be shot."

The striking truckers, many of them gathered at blockades at fuel depots at Elkton, Md., and Doswell, Va., vowed to continue their protests until the state and federal government officials accede to their demands, which include lowering diesel fuel prices, increasing the truck weight and length requirements on state highways, and raising the 55-mph speed limit.

In Maryland, where the truck weight limits are lower than the federal standards, the truckers have attempted to pressure Gov. Harry Hughes to raise them. A spokesman for Hughes said the governor is still considering the request.

At the Liberty Bell truck stop in Elkton, along the I-95 corridor near the Delaware border, the truckers' blockade continued yesterday for the 12th straight day. During that time the strikes have allowed only two drivers to refuel - one who was headed home for an emergency and another who was carrying penicillin to a hospital in Washington.

Ed Brennan, manager of the truck stop, said he sympathized with the truckers' plight, but added that he was not prepared to lose $21,000 a day for much longer. "If it don't end by tomorrow," he said "I'm going to take some positive action."

Business has been nearly as slow at Jarrell's Truck Plaza in Doswell, Va., which claims to be the world's busiest truck stop. Since midnight last Thursday, the daily volume of 40,000 gallons of diesel fuel has been cut in half. Business in the motel, the cafeteria, the fast food outlet and the All Faiths Chapel is off sharply.

"Look out the window there," said Thomas G. Jarrell, president of the truck stop company. "All you see are company trucks. We haven't had independents in here since Friday morning."

At midnight Friday, 25 independents brought their rigs into the truck stop about 25 miles north of Richmond and closed it down for several hours. Bill Scheffer, vice president of the Independent Truckers Association, went on the "Big John Trimble Show," an all-night radio program that is broadcast live from the truck stop. Jarrell said he chose to cooperate with the truckers because, "if we hadn't, they would have got belligerent."