Unseasonably warm weather is ruining much of this year's maple syrup crop, and consumers will find it scarcer and more expensive.

Vermont, which leads the nation in maple syrup production, may be headed toward its worst season on record.

"If we are fortunate, we will come off with half a crop," William Paine, Vermont's deputy commissioner of Agriculture, said today.

Thomas Todd, the president of the New York State Maple Producers, said, "This season's been so bad we don't want to talk about it."

The problem has been the weather. Cold nights, warm days and a good snow cover are the recipe for the best sap runs. This year, though, the weather has been too warm to generate strong runs. The maple sap is boiled into syrup.

The season is always short, tucked between the last days of winter and the first buds on the trees. Once the buds appear, the sap slows and its quality drops.

Paine said producers are hopeful some cold nights will return, recharging the sap flow and the industry's total output. But producers say that, with the temperatures so high, most sap now would not be of top quality.

Vermont produced 535,000 gallons of syrup last year; New York produced 325,000. The two states account for about 75 percent of the syrup produced in the nation. In New Hampshire, which produces about 92,000 gallons a year, Agriculture Commissioner Stephen Taylor said production is about one-third of normal.

"This is the worst season in 10 years," Taylor said.

David Marvin, the chairman of Vermont's maple promotion board, said his own Johnson sugaring operation has generated about 1,200 gallons compared with 4,000 last year. "The worst year we have had in our operation was 1975, but it was nothing like this," he said.

Vermont generates $15 million a year in income from the maple syrup operation. Marvin said the state's estimated 2,000 maple syrup makers could lose $7 million this year because of the weather.

A gallon of table-grade syrup generally costs from $22 to $24, while the dark heavier cooking syrup sells at $10. Producers forecast a retail increase of $7 on a gallon of cooking syrup.

In Alstead, N.H., at Bascom's Sugar House, the nation's second-largest syrup producer, Kenneth Bascom said he already has been offered $1.60 a pound for medium amber grade A syrup.

"That's the highest price I've ever heard for grade A maple syrup," he said.

Bill Clark, the president of the Vermont sugarmakers' association, said the taps at his Wells operation are generating about 50 percent of last year's output, but "we put out more taps, so our total will be about 60 percent."

Todd, the president of the New York association, said his Norwood operation, which is close to the Canadian border, has generated about half of its normal production.

Marvin said he expects the price of syrup will climb this year -- and some people will have to do without.

Vermont maple syrup sold for between $18 and $30 a gallon last year.