My property in northern Dekal co. Illinois is starting to be over run by what I believe to be MARAH FABACEUS ( California cucumber ). What is the best method to irradiate these plants. They grove very fast and multiply like mad. I have 30 acres of tree and prairie that are affected. I have tried Round up, slows em down, but does not kill, pulling at the root is almost an impossible task. With as many seeds that they put out I'm worried about what it might be like in four to five years.