NOTE: The US Agriculture Department will release its closely watched monthly supply and demand and crop production reports at 11 a.m. CDT (1600 GMT).
WHEAT - Down 2 cents to 5 cents
Wheat weakening after USDA report showed that winter wheat crop was rated 64pc good to excellent, unchanged from a week ago and topping the average market forecast of 63pc .
CBOT July wheat last traded down 2-3/4 cents at $5.04-3/4 a bushel. K.C. July hard red winter wheat was last down 6-1/2 cents at $4.46-1/2, and MGEX July spring wheat dropped 5-1/4 cents at $5.63-1/4.
CORN - Down 2 cents to 4 cents
Better-than-expected crop ratings also weighing on corn, as well as good weather that farmers are using to plant corn even though the optimum seeding window has passed.
Weekly crop progress and condition report showed that 83pc of corn planting was complete and the crop was rated 59pc good to excellent. Analysts were expecting planting of 83pc and good-to-excellent ratings of 54pc , according to the average of estimates in a Reuters poll.
CBOT July corn last traded down 3-1/2 cents at $4.12-1/4 per bushel.
SOYBEANS - Steady to down 2 cents per bushel
Soybean market under pressure from USDA report that showed 60pc of the US crop was planted, topping the average market estimate of 56pc .
Losses kept in check by expectations that farmers will not switch as much of their intended corn acreage to soy as was previously estimated, traders said.
Technical support for benchmark CBOT July soybean futures contract noted at 20-day moving average during overnight trading session.
CBOT July soybeans last traded down 1/4 cent at $8.58-1/4 per bushel.