Bugs are attracted to your backyard barbecue because they can smell the food. But they can also smell you. Citronella candles have a citrusy yet pungent scent to them as they burn. This aroma works to drive off flies, mosquitoes, and other flying insects by overpowering their olfactory senses. In doing so, they can’t smell your sweat, perfume, or deodorant. Nor can they smell your delicious barbecue, potato salad, and fruit salad. Consider placing a few citronella candles around the perimeter of your deck for decent coverage.