Dow AgroSciences and its lawyers at Orrick, Herrington & Sutcliffe are on a roll in their patent battle with Bayer CropScience. On Monday the Orrick team scored its second big defense win this fall against Bayer and its counsel at Milbank, Tweed, Hadley & McCloy, securing a ruling that Dow doesn’t infringe Bayer patents for herbicide-tolerant soybeans.

In a 28-page decision, U.S. District Judge Renée Marie Bumb, sitting by designation in Delaware, granted Dow’s motion for summary judgment of noninfringement. Bumb found that Dow held a valid sublicense from a Bayer licensee to develop and sell the Enlist E3 brand of genetically altered, herbicide-resistant soybean seed.

The case is of one three related patent challenges Bayer has filed over Dow’s Enlist weed control technology. In an earlier case first filed in 2010, the U.S. Court of Appeals for the Federal Circuit ruled last month that Dow doesn’t infringe a different Bayer patent. The third suit has been stayed pending arbitration.

The lawsuit that Bumb cut short on Monday was originally brought by Bayer in March 2012. Dow moved for summary judgement in May, claiming that it holds a valid sublicense to the patents from MS Tech, a company that licensed some of Bayer’s soybean assets after Bayer decided to divest them in 2003.

Judge Bumb held a two-day hearing on Dow’s summary judgment motion in June. In an unusual move, the hearings included live testimony from experts on English law, which governs MS Tech’s agreement with Bayer. In Monday’s decision, Bumb cited testimony from Bayer’s own expert witness that “divestiture does not include the retention of rights by Bayer.”

Peter Bicks of Orrick referred us to Dow for comment. “We repeatedly have expressed confidence in our legal position in each of the cases filed by Bayer concerning our Enlist technology, and the results we have obtained in these cases certainly validates our conviction,” Dow AgroSciences GC Ken Isley said in a statement.

Milbank’s Robert Koch didn’t immediately respond to our call. A spokesman for Bayer CropScience said the company is reviewing the decision and considering its options.