Even wheat, the grain and oilseed market's favourite, faltered on Wednesday.
It was not such a surprise that corn and soybean futures maintained their downswings, given the negative shock to markets on Monday from the US Department of Agriculture's discovery of extra domestic inventories of both crops, as of September 1.
By Chicago lore, selling sprees typically come in three-day packages.
'Significant frost risk'
However, wheat, which fared better from the inventory report, has been resolute up to now.
And there was extra cause, on the supply side, to buy the grain, as weather worries re-emerged in Australia, the southern hemisphere's top exporter, where dryness remains a worry in many areas.
Luke Mathews at Commonwealth Bank of Australia said: "Rainfall across the east coast grain belt yesterday was light, typically less than 4mm, and will do little to lift soil moisture levels.
"And grain producers will be closely monitoring forecasts for significant frost risk across much of the New South Wales grain belt later this week.
"Temperatures in central west New South Wales are currently forecast to fall below zero on both Friday and Saturday night, which if realised will likely result in yield damage."
'Domestic wheat pipeline is thin'
And this when frost, and a dearth of rainfall, has already hurt the crop in Argentina, the southern hemisphere's second-ranked exporter, leaving buyers relying on extra tricks to try to prise supplies from farmers viewing crops as a hedge against inflation.
"Intelligence out of Argentina is that the domestic wheat pipeline is thin, that trade is concerned about new-crop wheat yield prospects, and that Argentine mills are offering co-operatives a share of their profits if they can access co-op wheat stock," Richard Feltes at broker RJ O'Brien said.
This is especially significant for US hard red winter wheat values – note the needs of Brazil, which typically looks to Argentina for supplies, but is now buying from North America, and with talk of interest in European Union grain too.
"Look for further gains" in spreads in hard red winter wheat futures, as traded in Kansas City, Mr Feltes said, adding that the variety looked set to gain versus Chicago-traded soft red winter wheat and Minneapolis hard red spring wheat too (an outcome Agrimoney.com flagged on Monday).
Lights go out
And there are the growing concerns over winter wheat sowings in Russia and Ukraine to factor in, threatening to leave the world's bargain basement wheat store with limited volumes to offer next year.
However, wheat bears had a couple of decent points to rely upon, the first being the shutdown of the USDA, with the rest of the US government, thanks to what the department termed the "lapse" in funding following political deadlock.
"The US government shutdown had little discernible impact on the agricultural complex for the session, however, only time will tell if this changes," Mr Mathews said.
Sure, some statistic releases will be delayed, including potentially the key Wasde crop report scheduled for next Friday.
Sampling of fields for this report was due to have started on Tuesday.
'Exports could be affected'
But is the Wasde, while delayed, looks unlikely to be scrapped, there are some losses which could prove irreversible.
"Exports inspections may be unable to take place, meaning that the pace of exports for US grains could be affected," Joyce Liu at Phillip Futures said.
"This could adversely affect overseas demand of grains," a factor which has been a big prop for wheat prices, with US shipments beginning 2013-14 record fast, according to Macquarie.
And then there is the continuing decline in corn and soybean prices, under pressure too from strong harvest results.
"Early yield reports have been better than expected in a majority of the Corn Belt, and this includes areas that experienced a challenging end to the growing season," one broker said.
"There is a strong possibility that prices continue to grind lower in both complexes as a result of dismal demand and increasing production.
"The job of the market is to find the price level where we will pick up the demand that is necessary to reach the numbers that the USDA has written down.
"We believe that we can hit the demand figures but the price of corn and soybeans will be below these levels."
'May see some support later'
There were some straws for bulls to clutch.
Ms Liu said that "we may see some support later this week" to prices "because of forecasted rainfall extending into this weekend" which would hamper harvesting.
South Korea's Nonghyup Feed group tendered for 140,000 tonnes of corn, with the country also buying 99,000 tonnes of soymeal, albeit only a minority from the US.
However, with planting conditions improving in South America as an extra negative to prices, corn for December stood 0.8% lower at $4.35 ½ a bushel as of 09:55 UK time (03:55 Chicago time).
Soybeans for November stood down 0.2% at $12.65 ¼ a bushel, despite a relatively low estimate from FCStone overnight for the US yield, of 41.4 bushels per acre.
While above the 41.2 bushels per acre the USDA is factoring in, the number was below the 42 bushels per acre investors are believed to be factoring in.
(FCStone pegged the corn yield at 158.7 bushels per acre, above the USDA estimate of 155.3 bushels per acre.)
"I don't get the impression that the wheat markets are going to be able to sustain a rally, if the row crop markets remain weak," Brian Henry at Benson Quinn Commodities said.
And, indeed, wheat for December fell 0.4% to $6.78 ½ a bushel in Chicago, and 0.1% to $7.44 a bushel in Kansas.
Soft commodities had a brighter start, including raw sugar, which added to its gains of the last session, taking on 0.1% to 18.34 cents a pound in New York for March delivery, as investors continued to digest a huge delivery against the expiring October lot, and a Unica downgrade to Brazil Centre South production.
And cotton for December added 0.5% to 86.99 cents a pound, amid concerns of fresh rain damage to the US crop.
Cocoa for December eased by 0.4% to $2,623 a tonne in New York, and by 0.1% to £1,689 a tonne in London.
However, will the losses stick?
Recent weakness "could just be a short-term correction as the significant global deficit of cocoa in 2013-14 would support the cocoa market", Ms Liu said.