the results of the testing are set forth in table 1 below surfaces treated with 20 picaridin and 20 picaridin combined with zinc ricinoleate were similarly repellent 57 76 spatial repellency to the adult yellow fever mosquito at the 1 6 u03bcl cm 2 rate at the higher rate of 7 9 u03bcl cm 2 the 20 picaridin combined with zinc ricinoleate caused fumigant effects mosquitoes were knocked down following 15 minutes of exposure 81 spatial repellency 100 knock down in order to confirm the results of example 1 field studies were conducted with volunteers wearing short sleeves that left skin exposed volunteers were treated with picaridin on both arms and zinc ricinoleate in addition to picaridin on only the right arm the test solutions were mixed in the laboratory and volunteers were treated approximately 30 minutes before field exposure picaridin and zinc ricinoleate were sourced as described above and applied as follows 20 picaridin ready to use formulation applied neat 1 0 g per arm of this solution was applied via 8 sprays of the formulation from a 2 0 oz mist sprayer 1 0 g of zinc ricinoleate solution was applied to the right arm only via 1 spray from a 24 oz mist sprayer with trigger untreated control subjects and subjects treated with repellent and repellent zinc ricinoleate were exposed to a wooded area with observed mosquito populations in perry ga in mid june treated subjects were partnered in.