Today's opening bell at the NYSE was rung by the muckety-mucks who run the Teucrium Corn Fund (NYSE Arca: CORN), a newly launched tracker of maize futures we last updated on July 1 ("The BULLISH News From Yesterday's Market").

CORN's launch timing couldn't have been better. Not long after its June debut, surprisingly low stocks and planting intention reports sent already-skittery maize prices soaring. There's no better advertisement for a long-only fund than a bullish turnaround.

While corn (and CORN) traders are enjoying their recent gains, however, long-suffering ethanol investors have been buffeted. Just when the horizon seemed to be brightening, ethanol crush margins were, um, crushed by the price spike.

Ethanol Crush

The gross crush margin has sunk 20 percent since the end of April. Most of crushers' troubles coincided with corn's price rise, but weakness in another output—distillers' dry grains—added to their woes. DDGs are the fibrous remains of corn crushing, sold mainly as animal feed.

The softness in crush outputs doesn't seem likely to abate in the coming weeks. Livestock prices are falling, so herd building's not likely. Smaller herds? Lower DDG demand. And ethanol prices, already weighed down by record-high inventories, will likely aim lower as the summer driving winds down next month.

So, while the bell was joyously rung in New York for CORN today, ethanol crushers might have heard a more ominous knell.