Futures for December delivery surged for the third straight day, hitting a two-year high in the wake of Friday’s unexpectedly weak crop forecast.

The price of a bushel was up 40 cents Monday at $5.68, according to the Chicago Mercantile Exchange. That’s a dollar above the price that prevailed as recently as Oct. 2.

But corn stocks mostly didn’t come along for the ride Monday. Seed company Monsanto rose again, but the various tractor makers and fertilizer companies that tagged along Friday were flat to down Monday. The Teucrium Corn exchange-traded fund fell 3%, giving back a bit of its biggest-ever daily gain Friday.

Meanwhile, some observers were left scratching their heads by the all-over-the-place performance of the U.S. Agriculture Department in recent weeks. As FTAlphaville relates, commodities guru Dennis Gartman says recent volatility in the government’s corn estimates is giving investors a new set of doubts to deal with.

“Our faith in the USDA’s data is reaching a new low, and so too is the faith of others,” he wrote in a note to clients.