Rain Leaves Grains Sagging

Prices for grains were slipping Monday as traders worried that excess rain would boost crop yields and lead to an oversupply in the market.

Corn contracts were lower by 1.5% at $3.76 a bushel, while those for wheat were off 0.6% at $6.02 a bushel.

"Corn's fall has some oomph behind it," says Tobin Gorey, a commodities strategist at Commonwealth Bank of Australia, in a daily research brief.

He adds that not only is the technical picture looking increasingly bad for corn prices, but also it seems to be dragging on the wheat futures also.

In the meantime, traders will be watching the weather in the Midwest, where the level of rainfall later this week is considered critical to helping determine crop yields this season.

Turning to the agriculture complex, shares of

Corn Products International

(CPO)

were down 1.4%, while

Archer Daniels Midland

(ADM) - Get Report

was rising 0.3%.

Elsewhere, precious metals prices were softening, as well. Benchmark gold contracts were slipping $4 at $653 an ounce, and silver was off 16 cents at $12.86 an ounce.

The exchange-traded funds that track prices of the metals, the

streetTracks Gold Shares

(GLD) - Get Report

and the

iShares Silver Trust

(SLV) - Get Report

, were retreating 0.5% and 1.3%, respectively.

As for base metals, copper prices were down 5 cents at $3.33 a pound. The price was down more than that earlier in the session, but perked up after some new housing data was released midmorning.

The

PowerShares DB Base Metals

(DBB) - Get Report

, which tracks the prices of copper and industrial metals, was down 0.9%.