GRAINS-Corn eases further from 18-month high

Updates at 1035 GMT, changes dateline

PARIS/CANBERRA, Feb 25 (Reuters) - U.S. corn futures edged down on Tuesday as improving crop weather in South America and expectations of increased planting by U.S. farmers encouraged profit-taking following last week's 18-month high for prices.

Wheat tracked corn lower, with pressure also coming from easing concerns about cold weather damage to U.S. and Russian crops.

Soybeans were almost unchanged after falling on Monday.

Renewed investor concerns about U.S. tariffs, after President Donald Trump said proposed levies on imports from Mexico and Canada were on track to be implemented, were also weighing on grain markets, which fear reprisals against U.S. agricultural exports.

Grain traders were also turning their attention to a U.S. Department of Agriculture conference later this week at which the USDA will give early supply and demand projections for next season.

The most-active corn contract on the Chicago Board of Trade (CBOT) Cv1 was down 0.45% at $4.94-3/4 a bushel at 1035 GMT.

"We expect that U.S. plantings will be up as a result of attractive pricing, and this along with rain forecasts for Argentina and Brazil is taking some of the shine off corn futures," said Andrew Whitelaw at agricultural consultants Episode 3.

An acceleration in planting of Brazil's safrinha corn crop has also tempered worries about late development that could hurt yield prospects.

CBOT wheat Wv1 was down 0.84% at $5.88-1/2 a bushel while CBOT soybeans Sv1 inched down 0.02% to $10.47-1/4 a bushel.

Wheat export prices in Russia, the world's biggest wheat shipper, continued their upward trend last week due to a stronger rouble and lower shipments, though traders said export competition from other countries remained stiff.

Russia's state weather forecaster, meanwhile, said late winter frosts in the country's southern breadbasket regions were unlikely to inflict significant damage on winter crops.

"Recent concerns related to cold snaps, especially in Russia, now seem to be dissipating," Argus analysts said in a note.

In soybeans, consultants AgRural trimmed their forecast for Brazil's crop to 168.2 million metric tons from 171 million tons, but that still represents a record-breaking harvest.