Monsanto Co. and other seed makers reported a threefold increase last year in U.S. farmers caught violating requirements for planting genetically modified corn. The data relates to farmers planting seeds that are genetically modified to produce a toxin derived from Bacillus thuringiensis, or Bt, a natural insecticide. The Environmental Protection Agency requires the growers to plant an adjacent area - a so-called refuge - of non-Bt corn so that bugs don’t become immune. About 41 percent of 3,053 farmers inspected in 2011 failed to fully comply with the refuge requirement