Raw sugar futures slid to a four-month low and arabica coffee dropped to an 18-month trough on Monday as the prospect of bumper supplies from top sugar and coffee producer Brazil and early strength in the dollar undermined both markets.
Cocoa settled higher.
Sugar lost ground as the harvest of Brazil's centre-south cane crop loomed and Liffe recorded one of the largest deliveries of Indian sugar in recent memory.
The delivery included 2,500 lots (125,000 tonnes) of Indian sugar.
New York's May raw sugar contract declined 0.47 cent or 2.01 percent to finish at 22.90 cents per lb, its lowest settlement since mid-December 2011.
London August white sugar futures fell $15.60 or 2.5 percent to settle at $595.40 per tonne.
"There's too much sugar for the demand that exists right now," said Mike McDougall, a vice-president for brokerage Newedge USA in New York.
He pointed in particular to the white sugar delivery and the outflow of Indian sugar in the market.
Another reason for the weakness in sugar futures was the poor tone of last week's close.
"We expect the weakness in the markets to continue and we are not satisfied that enough liquidation has taken place," Nick Penney of brokerage Sucden Financial said.
The question now is whether raw sugar will drop below the 23 to 29 cents range that had been in place since November 2011, McDougall said.
The supply picture was underscored by news last week that Brazilian sugar industry association Unica forecast the main centre-south crop would yield 33.1 million tonnes of sugar in 2012/13, up 5.7 percent on the year.
It pegged the centre-south cane crush at 509 million tonnes.
A London-based broker said the sugar number was higher than expected, although the cane number was neutral.
The Unica data followed a forecast by Conab, Brazil's government crop supply agency, that sugar production would rise to 38.9 million tonnes in 2012/13.
Thai raw sugar prices could slip this week because of rising supply in the main producing countries.
Arabica coffee futures fell to an 18-month low, pressured initially by the stronger dollar and follow-through weakness from last week.
A firmer greenback makes dollar-denominated commodities more expensive for holders of other currencies.
The market fell to its lowest since October 2010 in relatively heavy volume and on continued May/July spreading ahead of the spot contract's first notice day on Friday.
Outside of the May/July spread activity, the session's weakness was believed to have come from computer-driven speculative sales, dealers said.
July arabicas on ICE fell 4.35 cents or 2.41 percent to end at $1.7585 per lb, having touched an 18-month low in the second position at $1.739.
Liffe July robusta coffee futures slipped $9 to close at $2,003 per tonne.
Cocoa futures ended higher.
US cocoa values firmed in choppy dealings, pressured earlier by a weak pound against the dollar then buoyed as the British currency turned slightly positive.
July cocoa on ICE climbed $26 or 1.2 percent to finish at $2,226 per tonne.
Liffe July cocoa added 10 pounds to finish at 1,468 pounds per tonne.
The May contract moved to a steep premium against July last week, and on Monday soared to around $67, the highest for the spot contract in a year.
The premium closed at $48 on Friday.
First notice day is on Tuesday.