Although Citronella candles may invoke the scent of summer, they are among the least effective mosquito repellents available, according to a study published last week in the Journal of Insect Science.
Researchers at New Mexico State University determined that spray-on repellents containing DEET or PMD are the most effective options available.
The researchers studied 11 different types of repellents, including spray-ons, citronella candles, and wearable devices. Whereas the candles had no effect on mosquitoes, chemical sprays performed rather well.
The OFF! Clip-On was the only wearable device that performed well. Other wearable devices—including bracelets embedded with herbal extracts and sonic devices which claim to use high-frequency sounds—were determined to be ineffective in repelling mosquitoes.
The most effective repellents in the study were Cutter Lemon Eucalyptus and Ben's Tick & Insect Repellent sprays. The study also concluded that bug sprays “based on essential oils often have shorter repellency effects” than those which include chemicals like DEET or PMD.
“These findings are extremely important for consumers because they need to be aware that there are mosquito repellent products available that are ineffective,” Stacy Rodriguez, one of the researchers, said in a statement. “While the labels of many products make strong claims, some products simply don't work.”
Those traveling to Zika-affected countries can check out our guide to the best bug sprays for travelers when packing bags.