DEET and permethrin can damage synthetic materials, plastic on eyeglass frames and watch crystals. Lighter colors don’t attract mosquitoes as much as darker clothing. Tuck your pants into your socks.

For example, the label on Sawyer’s permethrin aerosol spray says that a 4.5-ounce bottle will treat a shirt, a pair of pants, and a pair of socks. Let the clothes dry completely. Before you wear ...