Wheat prices ended at a four-month high in Chicago, and in Paris at their highest since June, boosted by concerns over Black Sea supplies fostered by a double whammy of frost and export curb concerns.

Arkady Zlochevsky, head of the Russian Grains Union, an influential industry group, said that Moscow was considering introducing an export levy from April to curb shipments, on pace to far exceed a government ceiling of 23m-25m tonnes.

The comments stoked tariff fears viewed as further accelerating demand for Russian grain, which has a reputation for keen pricing, before any levies are introduced, in what would mark a second successive season to witness export curbs.

"Grain exports showed surprising dynamics in January," in terms of strong demand, Mr Zlochevsky said.

'Going crazy'

However, cold weather is hindering efforts by former Soviet Union ports to keep up with demand.

Tuesday's closing wheat prices

Chicago: $6.66 a bushel, +3.3%

Paris: E215.50 a tonne, +3.1%

Kansas: $7.15 ½ a bushel, +2.6%

London: £168.40 a tonne, +2.1%

Minneapolis: $8.28 ½ a bushel, +1.1%

Prices for March contracts except in London, where price is for May contract

"Exports from the Black Sea are hampered by the current cold temperatures," Agritel's Kiev office said, adding that loadings were "are impossible due to ice" in the Azov Sea, which runs off the north east of the Black Sea.
In the US, Jerry Gidel, at broker North America Risk Management Services, said: "People are worried they are not going to get the grain out through the terminals, and that if they wait two weeks, they will have to see if there are grain tariffs or not.

"The market is going crazy out here."

'More susceptible to winterkill'

The cold weather has also provoked concerns of winterkill marring a good start for autumn-sown grains in Russia, and worsening prospects further for drought-depleted crops in Ukraine.

"With low snow cover across parts of Russia and Eastern Europe, the threat of winterkill has raised its head," UK traders at a major commodities house, with significant Black Sea operations, said.

With crop development in many areas advanced beyond normal levels by a winter which has, hitherto, been mild, seedlings "are more susceptible to winterkill than last year".

Weather is also emerging as an increasing threat to spring wheat in northern US and Canada, where a dearth of precipitation evident in December rains as low as 25% of normal levels in some areas is provoking increasing concerns.

"Dryness poses an emerging threat to [Canada's] 2012-13 wheat crop," Rabobank said.

Prices rise

Russia attempted late on Tuesday to tackle uncertainty over exports, when Viktor Zubkov, deputy prime minister, revealed a meeting on Thursday to discuss curbs.

Earlier, Ilya Shestakov, deputy agriculture minister, said the government would in "about two weeks" be able to announce a decision on export curbs.

"We are actively discussing it. No one is denying the likelihood," Mr Shestakov said.

Paris wheat for March ended up 3.1% at a seven-month closing high of E215.50 a tonne.

London's best-traded feed wheat lot, for May delivery, gained 2.1% to £168.40 a tonne, the contract's highest finish for four months.