I can't remember where I read it, but it said that Marigolds work to repel some insects. ANd they seem to be working for me.
Prior to planting the Marigolds, I was seeing bugs on my Mt. Hoods daily, sometimes twice a day, even if I sprayed insecticidal soap in the morning. SInce planting them on June 23 I've only seen bugs on the Mt. Hoods about 2 times, and significantly seen a decrease in my leafs getting eaten. Almost not a problem anymore, and I haven't had to spray the soap since.