If you’d prefer not to slather on chemicals, there’s oil of lemon eucalyptus (OLE). We found this 30-percent OLE formula to be just as useful as DEET against mosquitos in Louisiana’s Bayou Sauvage National Wildlife Refuge, though we needed to reapply every few hours (it also works on ticks and black flies). “The smell and non-greasy feel are much more pleasant than DEET,” one tester says. Note: OLE isn’t considered safe for kids under 3 (DEET is, though). $5; 4 oz.