By Christopher Hinton

NEW YORK (Dow Jones) -- Monsanto Co.'s second-quarter net income fell 3.5% due to a decline in sales of its Roundup herbicide, financial results showed Thursday.

Shares of the St. Louis-based supplier of herbicides and genetically engineered seeds (MON) were virtually flat at $81.97 each. Still, the stock has lost more than 42% of its value since hitting an all-time high last June at $145.80 each.

For the three months ended Feb. 28, Monsanto reported net income fell to $1.09 billion, or $1.97 a share, from $1.13 billion, or $2.02 a share, earned in the year-earlier second quarter.

Quarterly sales rose 8% to nearly $4.04 billion.

On an ongoing basis, Monsanto said second-quarter earnings amounted to $2.16 a share. Analysts polled by FactSet Research had been looking for a profit of $2.06 a share, on average.

"Versus our estimate, the beat was driven by higher than expected profits in seeds & genomics, taxes, minority interest and share count," said Laurence Alexander, an analyst with Jefferies& Co.

Second-quarter profit at its agricultural productivity segment fell 5.7% to $544 million as sales for Roundup and other glyphosate-based herbicides declined 21%. In the prior-year quarter, sales of Roundup surged ahead of a publicized price increase, Monsanto said.

Quarterly profit generated the company's seeds and genomics segment rose 21% to nearly $2 billion as sales climbed nearly 20% to just over $3 billion.

For the full fiscal year, the company forecast earnings of $4.23 to $4.33 a share, or $4.40 to $4.50 a share on an ongoing basis. Analysts' consensus for earnings in fiscal 2009 stands at $4.65 a share, according to FactSet's survey of estimates.