12:45PM New York – Agriculture stocks plunge on earnings miss from Mosaic and ratings downgrade on Potash Corp and Agrium Inc.

Agrium Inc (AGM: chart) gained 4.5% or 31 cents to $7.16 a day after it gained nearly 60% on the completion of $65 million debt offering.

Con-way Inc (CNW: chart) fell 14.72% or $6.28 to $36.65. The trucking company lowered its full-year earnings from continuing operations to between $2.60 and $2.80 per diluted share from the earlier estimate between $3.00 and $3.40.

Constellation Energy Group Inc (CEG: chart) surged 10.2% or $2.44 to $26.20 after the merger partner MidAmerican Energy completed its 14-day due diligence of its trading records and the company expressed satisfaction with the transaction.

Constellation Brands, Inc (STZ: chart) plunged 7.26% or $1.59 to $20.03 after it reported second quarter revenues rose 6% to $1.24 billion from $1.17 billion a year ago. Net loss in the quarter was $23 million or 11 cents per diluted share compared to net income of $72 million or 33 cents per share, a year ago.

eBay Inc (EBAY: chart) fell 7.39% or $1.53 to $19.32 after Morgan Stanley lowered rating and said that auction trends on the markets are deteriorating.

General Electric (GE: chart) dropped 10% after it complete $12.2 billion in public offering. The stock declined $2.32 to $22.18. The engineering giant stock has steadily declined as investors fear that mounting losses in its financial division will drag the earnings lower.

Las Vegas Sands Corp (LVS: chart) fell 13.79% or $4.32 to $27 and fell below its intra-day price since it went public on December 15, 2004 at a price of $29 a share.

Marriott International, Inc (MAR: chart) dropped 1.3% or $0.28 to $24.80 but plunged as much as 10% after its profit declined more than expected and the company issued a weak 2009 earnings guidance.

The Mosaic Company (MOS: chart) dropped 31% or $20.54 to $46.97 after it reported first quarter net income of $1.2 billion or $2.65 a share compared to $305.5 million or $0.69 a share. The average phosphate price in the quarter was $1,013 per ton. The company reported earnings of $2.83 a share excluding the mark-market losses from credit derivatives and still missed the target. Farmers may face difficulty in getting loans if credit conditions remain tight and corn price keep falling.

Bunge Ltd. (BG: chart) plunged 21% or $13.06 to $49.98 as agriculture stocks declined. Merrill Lynch downgraded Potash and Agrium to ‘underperform’ from ‘buy.’

Potash Corporation of Saskatchewan Inc (POT: chart) plunged 24.15% or $30.92 to $97.12 and Terra Industries (TRA: chart) plunged 22% or $6.09 to $22.31 and now fallen nearly 50% in the last seven days of trading from as high as $44. CF Industries Holdings, Inc (CF: chart) dropped 26.04% or $23.20 to $65.56. Intrepid Potash, Inc (IPI: chart) fell 21.62% or $6.40 to $23.25.

Standard Microsystems Corporation (SMSC: chart) dropped 7.71% or $1.96 to $23.60 after the integrated circuit maker reduced sales and profits estimate in its latest quarter, and forecast lower demand for its products in the next quarter.