Our most favorite for of bug defense is a ThermaCELL. (No they did not pay me to say this or give me a free one to try out.) I was a little sceptical at first when my husband suggested we try a ThermaCell, but Bass Pro had them on sale so we went ahead and bought one. I wish we had bought one years ago! If this one dies......well, I don't want to think about that.
My next favorite are those weird looking bug bracelets. We originally bought them for our nieces and nephew to try out but now they are always in my day bag. They work really well and if you only use them for a little while, you can put them in a plastic baggie and reuse them later (a day or 2 later, not weeks later). I found out that if the bugs are messing with the back of your neck, put the bracelet around your ponytail! My nephew kept the bugs away from his face by putting a bracelet around the brim of his hat. The kids love wearing them so much that sometimes we find them still wearing the bracelets when they get out of bed in the morning. The bracelets are not oily so they don't leave a residue on your skin, in your hair or on your clothes (or bedding).