For as long as I have been appliquéing (since the mid 80's) it was recommended to use starch. I would think if there were a discoloring issue or a bug problem it would be well known. My DD is a teacher, and she found this great sports fabric that she wanted to put on the wall instead of paper background. The school has a silverfish problem with all the books and paper products around. That fabric is the only thing they don't bother. She never washed it, so I believe it is the chemicals the mfg used on it that keeps them away. So if you are not washing the fabric it may be the critters won't be attracted.