Democratic U.S. Senate candidates Tom Fiegen and Bob Krause have spent much of the primary lead-up attacking Roxanne Conlin, the front-runner in the race for the nomination. However, the two underdogs have turned on each other this week, tossing attacks back and forth via Facebook and Twitter.

On Tuesday, Krause’s campaign issued a statement criticizing Fiegen for not supporting ethanol subsidies.

Fiegen swung back, using Twitter to clarify his position on ethanol: “Memo to Bob Krause: I have been a loyal buyer of ethanol since we called it gasohol. I’m not pulling the plug-I’m weaning ADM & other pigs.

Then on Thursday night, Krause strung together eight Twitter updates stressing the importance of ethanol subsidies to Iowa farmers. “What would happen to state tax revenues if the price of corn went down 50 to 75 cents per bushel over the long term because of Fiegen?

And finally, the spat turned nasty with Fiegen’s rebuttal a couple hours later: “Memo to Bob K: I’m tired of feeding PIGS tax money so that a few pennies flow to family farmers, workers & poor. You & [Conlin] can sleep w/PIGS.