WHEAT - Down 4 to 8 cents per bushel Lower on technical selling and a lack of fresh supportive news.
CBOT September wheat fell to a session low ahead of the break in trade. Strength in the dollar lends pressure.
Plentiful world supplies and poor export demand continue to hang over the market.
The European Union's crop monitoring service cut soft wheat yields to 5.86 tonnes per hectare, from 6.10 estimated in July.
Romania reaped a bumper wheat crop of 8.4 million tonnes this year, 7 percent up from 2015 at a 10-year record high yield, Agriculture Minister Achim Irimescu said on Sunday.
CBOT September soft red winter wheat last down 7-3/4 cents at $4.19-1/4 per bushel; K.C. September hard red winter wheat down 3-1/2 cents at $4.15-1/4; MGEX September spring wheat last down 1-1/4 cents at $5.29-1/2.
CORN - Down 2 to 3 cents per bushel Light profit-taking setback after a six-session advance in the CBOT December contract. Market fell to session lows just ahead of the break in trade.
Traders await findings from the annual Pro Farmer Midwest Crop Tour, which begins on Monday with field scouting in South Dakota and Ohio. Pro Farmer is expected to release US corn and soy yield estimates on Friday, after the tour concludes.
The European Union's crop monitoring service cut its forecast for the average maize yield in this year's EU harvest to 7.23 tonnes per hectare, from 7.42 seen in July, suggesting dry weather has impacted output in the bloc.
CBOT December corn last down 2-3/4 cents at $3.41 per bushel.
SOYBEANS - Down 3 to 5 cents per bushel Lower on technical selling, with the benchmark November contract hitting a session low just ahead of the break in trade.
Good weather for final stages of crop development in US Midwest weighs on market. Market underpinned by strong export demand for US soy, especially from China.
Traders await findings from the annual Pro Farmer Midwest Crop Tour.
The USDA said private exporters sold 120,000 tonnes of soybeans to unknown destinations for 2016/17 delivery.
Malaysian palm oil futures fell to their lowest in over a week, tracking rival oils and as expectations of a pick up in output offset improving export demand.
CBOT November soybeans last down 4-1/4 cents at $10.00-1/4 per bushel.