Chicago Board of Trade corn futures fell to contract lows Tuesday on broad commodity weakness tied to escalating US-China trade tensions and favourable weather that has boosted crop prospects, traders said. Bargain buying lifted futures off session lows. CBOT July corn settled down 2-1/4 cents at $3.53-3/4 per bushel after sliding to a contract low of $3.38-3/4. New-crop December corn ended down 1-3/4 cents at $3.75-1/2 after recording a contract low at $3.60.

Global stock markets tumbled with agricultural commodities after US President Donald Trump threatened to impose a 10 percent tariff on another $200 billion of Chinese goods, a threat that China's commerce ministry described as "blackmmailing," vowing to retaliate. Favourable US crop weather added pressure.

The USDA late Monday rated 78 percent of the US corn crop as good to excellent, up from 77 percent the previous week. Analysts on average had expected ratings to decline by 1 percentage point.

Copyright Reuters, 2018