Farmers in southern Illinois are among many growers worried that a brutally cold winter could threaten seasonal crops such as winter wheat.  Thompsonville farmer Tom Saxe tells WSIL-TV that winter wheat might be compromised by the harsh winter.  That’s because the elements may make the plant more susceptible to secondary diseases that would come on during the spring.  Portions of southern Illinois already have gotten nearly 18 inches of snowfall this winter, along with temperatures more than two degrees below normal through December and parts of January.  It’s too early to tell what winter’s impact may be on the winter wheat crop.  Corn and soybeans won’t be planted until the spring.