EDINBURG, VA., AUG. 13 -- This summer's dry spell hasn't hurt the agriculturally rich Shenandoah Valley's newest and most glamorous crop, the vinifera grape.

Jack Foster, winemaker for the Shenandoah Vineyards here, predicts a "very, very nice harvest" when the first grapes of the season are crushed here beginning next week.

"Our mature vines are not hurt by a lack of rain," Foster said, but he added that newer plantings are "sensitive to heat stress" and suggested that irrigation might be necessary if Virginia's wine industry is to continue to grow.

Foster's attentive wine-tasting audience during a special tour today included Gov. Gerald L. Baliles, whose three-day tour of the Shenandoah Valley is the fifth "work week" of his administration.

Everywhere the governor stopped today, he encountered evidence that the long tentacles of the Washington metropolitan area are stretching deep into the heart of this lush, tranquil valley.

The Washington area was frequently named as a market for the valley's goods and services: wine, kitchen cabinets from the new Merillat plant in nearby Mount Jackson, and weekend getaways at Mary's Country Inn, a bread-and-breakfast inn in Edinburg operated by Mary Houston, a Fairfax County art teacher, and her husband, Jim Clark, a retired Navy department employe.

At a luncheon in New Market with area officials, Baliles urged farmers to adopt a "demand-side strategy" that might require them to abandon traditional crops, instead seeking out newer, expanding markets.

One example, he said, is the nursery industry. Baliles said the demand for shrubs and small trees at suburban office parks and developments in Northern Virginia is growing by 10 to 20 percent a year, yet 85 percent of such plantings come from out of state.

And the state's massive highway building program, whose financing has been boosted by a $422 million tax increase approved last year, makes it economical for farmers to "go through your fields a third time and collect straw" that can be sold to highway contractors, the governor said.

The Washington area's influence was present even during the question period. James Clark, a member of the Clarke County Board of Supervisors, referred to his experiences as a high-ranking transportation official in the District in expressing concerns about the adverse effect increased truck traffic is having on the quality of life in his new home 60 miles west of Washington.

Northern Virginia is the primary market for Shenandoah Vineyards, whose blanc, at $4.45 a bottle, is a big seller there, according to proprietor Emma Randel.

Randel, who with her husband began growing grapes for wine here in 1971, told Baliles that her winery is "selling almost all we can bottle."

The wine industry is booming in Virginia. Since 1979, the number of wineries in the state has increased from six to 34. And since the first modern winery, Piedmont, was uncorked near Middleburg (as with most things Virginian, Thomas Jefferson pioneered winemaking in the Old Dominion), annual production has reached 280,000 gallons from 1,600 acres, ranking Virginia seventh in production nationally.

The Shenandoah Valley is one of five viniculture areas in Virginia designated by the federal Bureau of Alcohol, Tobacco and Firearms, which means that, like the famous wine-growing regions of France, its wineries can carry that appellation on their labels if they use grapes mostly from their vicinity. (The others are Monticello, Rocky Knob, North Fork of the Roanoke and Northern Neck-George Washington Birthplace).

Randel praised a decision by the state that bars the sale of non-Virginia wines in the state's ABC stores, which has boosted sales for smaller wineries in particular.

But she had a complaint, too.

She said her winery cannot afford to sell its wine beyond the state's border because other states add their own taxes on to the price of Virginia wine in retaliation for Virginia's imposition of a tax of 30 cents a liter on all wine sold in the state.

So Randel asked the governor to support a law that would, in effect, say: if you don't tax our wine, we won't tax yours.

Baliles said that as much as he likes Virginia wine -- Naked Mountain white is a favorite -- he opposes reciprocity because it would favor out-of-state wine producers at the expense of Virginia wineries.