* Robusta hits lowest level since March, Vietnam crop weighs
* Arabica coffee edges up but remains close to Monday's lows
* Sugar prices edge up as market awaits Brazil output data
(Adds quotes, updates prices)
LONDON, Nov 6 (Reuters) - Robusta coffee futures on Liffe fell to an eight-month low on Tuesday with the market weighed by the prospect of a large harvest in Vietnam while ICE arabica coffee turned higher after setting a 4-1/2 month low during the prior session.
Raw sugar and cocoa futures on ICE were slightly higher.
January robusta coffee futures were off $18 or 0.9 percent at $1,934 a tonne at 1235 GMT after setting at eight-month low for the second month of $1,932.
Coffee prices in Vietnam, the world's top robusta producer, have fallen to their lowest in nearly 11 months, squeezed by a bumper harvest, while this month's export volume could ease from October's figure, traders said.
Technical selling added to the downward pressure caused by expectations of strong Vietnamese production, analysts said.
``We came down through the $2,000 level because of the Vietnamese crop. There is technical pressure because the fundamentals have been factored in to a degree,'' said Andrea Thompson, analyst at CoffeeNetwork, part of INTL FCStone.
Thompson noted said that after breaching a key support level at $1,960 on Monday, there is little technical support before $1,700.
Macroeconomic concerns were also playing a part as the U.S. headed to the polls for presidential elections.
``The other concerns are global growth and the U.S. economy, with the focus on the election today. If you don't get a sustained pick up in the global economy that will eventually have an impact on not just coffee demand but commodity demand,'' Thompson said.
Strong global demand was expected to underpin the market in the long term.
``My expectation would be that fundamentals would kick in again and people will start to think that even with this bigger crop, (robusta) demand growth has been good and we're still going to have a tight market,'' Thompson added.
December arabica coffee futures were up 0.40 cents or 0.3 percent at $1.5130 per lb. The contract hit $1.5080 on Monday, the lowest level for the front month since June 21.
``My expectation now is that prices will likely break below the June lows, triggering a massive sell stop onslaught, and then reverse higher to initiate a buy signal and seller exhaustion,'' said Shawn Hackett of Hackett Financial Advisors.
The front month fell to $1.4820 in June, its lowest level since June 2010.
COCOA, SUGAR RISE
ICE December cocoa rose $11 or 0.45 percent at $2,455 per tonne with the market rangebound.
Dealers continued to keep a close watch on the outlook for main crops in West Africa with drier weather seen reducing the threat posed by black pod disease.
Cocoa production from top grower Ivory Coast's October to March main crop will reach around 1.06 million tonnes with disease and cross-border smuggling likely to have little effect on output, Swiss chocolatier Barry Callebaut said on Monday.
Benchmark Liffe March cocoa futures were 2 pounds higher at 1,582 pounds per tonne.
March sugar futures were up 0.21 cent or 1.1 percent at 19.54 cents a lb with the market edging away from a six-week low of 19.18 cents set last week.
Dealers said the market remained weighed by ample supplies with traders awaiting an update on production in the key centre-south region of Brazil, expected later this week from sugar industry association Unica.
``Unica is expected to release its next report detailing progress in the second half October soon so we will have some fundamental update to mull over. In the meantime, we still expect a test of the recent lows and we will sit back and watch the result of the U.S. Presidential election,'' said Nick Penney of Sucden Financial.
December white sugar on Liffe rose $6.20 or 1.15 percent at $543.80 per tonne.
Buyers from the Middle East have been chasing white sugar from India and Pakistan for nearby shipment, but Thai raw premiums slipped as the new harvest approaches and more sweetener from Brazil enters the market, dealers said on Tuesday.
(Reporting by Nigel Hunt and Clare Hutchison; Editing by Alison Birrane)