PRESQUE ISLE — Potato marketing sleuths in Maine and Canada were predicting a rosier price picture for United States fall potato growers Friday than they were a month ago, thanks to a much lower American french fry inventory and questionable yields in Idaho.

Maine Potato Blossom Festival audiences were told last month that an expected production of 345 million hundredweight from states that harvest potatoes in the fall apparently would coincide with demand.

Harry Fraser, editor of a respected Canadian potato newsletter, added that apparently with only 5 million or 10 million hundredweight fewer potatoes, there would be break-even prices.

The latest edition of Fraser’s Potato Newsletter said, in effect, that with the total U.S. french fry inventory at 8 percent below last year’s level at the end of July, there could be a higher processing demand for new crop potatoes and a more lucrative market for grower prices as supplies dwindled.

“With process buying as the early price engine, a crop of 345 million hundredweight could result in break-even prices over the coming season,” Fraser said. “In 1987 and 1988, processors cruised through June with plenty of old crop potatoes still around. That didn’t happen last year, and there were even fewer processing russets left this year. Pacific area holdings in Washington and Oregon showed the biggest drop in french fry inventory of all, down 21 percent.”

Most processors ran as many “new” potatoes as they could last summer, but that didn’t keep inventories from falling “perilously low. It could take until December for processors to rebuild inventories to the comfort zone,” Fraser said. “That’s supposing there’s a normal crop.”

Stanley P. Greaves, of the Maine Farmers Exchange dealership in Presque Isle, agreed with Fraser.

“I can see nothing wrong in his logic,” said Greaves. “We could very well have a manageable crop. Yield and production for 1990 are not yet determined, however.”

Fraser said Idaho yields were questionable. “Some fields show signs of stress,” he added.

A cross-section of agronomists, quoted in Idaho newspapers, said the average yield could be down there 10 to 15 percent.

Dr. Steven B. Johnson, a potato specialist of the University of Maine Cooperative Extension, said Aroostook County’s potato crop appeared to be “average to above-average, picture-perfect. Three inches of rain the third week of July exploded growth. We could still use some more rain.”

Fraser said he toured most of the Maine and New Brunswick potato areas recently. “An average crop in Maine; the same in New Brunswick,” he said.

Maine’s planted acreage remained stable at 80,000, the same as the 1989 crop and 1,000 acres less than in 1988.