Certain components of citrus fruits and oxidation products of limonene are effective deterrents, repellents and / or spatial inhibitors for mosquitoes and biting midges. The compounds that have been found to be deterrents, repellents and inhibitors for mosquitoes and biting midges are neryl acetate, citronellyl acetate, geranyl acetate, hydroxy-p-cymene, citral, α-terpineol, citronellal, linaloyl acetate, citronellol, terpen-4-ol, tetrahydrocarvone, products of oxidized oxidized limonene inclusive of d- and l-carvone, (+) limonene oxide, (−) limonene oxide, cis and trans carveol, a diol and an aldehyde, and mixtures thereof.