The Canadian Wheat Board says this year could be even worse than 2010, sucking an additional $1.5 billion to $2.5 billion out of the Prairie economy.

On Tuesday, the board said between 2.4 and 3.2 million hectares of farmland is still unseeded across the Prairies this year because of wet weather.

"This is occurring at a time when grain prices are extremely high, adding insult to injury," said Bruce Burnett, the board's director of weather and market analysis.

"Many farmers in the wettest areas have planted next to nothing this spring, while others are watching their newly emerged crops drown," Burnett said.

The seeding estimate is only marginally better than last year — another wet planting season — which set a record low that stretched back to 1971.

But Burnett also forecast yields that could be lower than last year due to other factors, such as an even later start to seeding this season.

Production expected to fall by 700,000 tonnes

He said it's too early to pin an accurate dollar figure on what an estimated 700,000-tonne drop in wheat production could cost, but agreed it could fall somewhere between $1.5 billion and $2.5 billion.

The wheat board is estimating production of all wheat at 20.3 million tonnes — down from 21 million in 2010. The five-year average is 22.4 million tonnes.

Burnett said weather over the next two weeks will be critical if there is any hope of lifting expectations for seeding.

The situation is expected to add to upward pressure on world wheat prices, which have increased 70 per cent over the last year. While wet weather has hit many parts of western North America, drought has affected wheat crops in France, Australia and China.

Southwestern Manitoba and southeastern Saskatchewan have been hardest hit, but there are pockets of wet areas from the Red River Valley in Manitoba to Lethbridge, Alta.

Overall, the board said seeding is about 86 per cent complete across the Prairies; normally at this time of year, seeding is entirely done.

With files from The Canadian Press