Roundup, the former cash cow of Monsanto (NYSE: MON), is an official train wreck. After its sales fell 14% during its fiscal 2009, they've crashed an additional 54% during the first half of fiscal 2010, because of increased generic competition in herbicides. The only question now is how quickly Monsanto is able to clean up the mess and get back on track.

Monsanto's saving grace, its seeds business, continues to grow. Sales rose 6.8% in its second fiscal quarter. That's not bad, since it competes with offerings from DuPont (NYSE: DD), Dow Chemical (NYSE: DOW), and Syngenta (NYSE: SYT), but it won't make up for the lost profit from Roundup's fall. Excluding one-time items, earnings per share fell 19% last quarter. Ouch.

In order to accelerate seed sales, Monsanto needs to convince farmers that its new higher-yield seeds -- SmartStax corn and RoundUpReady2 soybean -- are worth the added cost. So far, that isn't happening en masse

Corn prices, which have fallen since the beginning of the year, haven't exactly helped the situation. Like Agrium (NYSE: AGU), Mosaic (NYSE: MOS), PotashCorp (NYSE: POT), and other fertilizer companies, seed producers are somewhat dependent on the price of commodities. If farmers get more for the end product, they can afford to pay more for the inputs.

After a couple of disappointing quarters, Monsanto warned that it'll likely be at the low end of its previous non-GAAP guidance of $3.10 to $3.30 per share. The company also said it's unlikely to hit its long-term goal of doubling 2007 gross profits by 2012.

That's disappointing for investors, but at least the company isn't making any stupid short-term decisions just to reach a self-inflicted goal. Getting the trains back on the track may take longer than expected, but the long-term health of the company seems viable.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Syngenta is a Motley Fool Global Gains selection. The Fool has a disclosure policy.