Mint is the common name for plants in the genus Mentha, which is in the family Lamiaceae, also known as the mint family. The genus Mentha contains an estimated 13-24 species, although this is complicated by natural hybrids which occur where the ranges of different Mentha species overlap. Commonly cultivated species include spearmint, peppermint, and pennyroyal.

Mints are rich in fragrant oils, which give them their distinct smell and flavor. The primary components of mint essential oils are menthol and menthone. Menthol provides a cooling sensation and is used in various remedies and medicines. Menthone is used in perfumes and flavorings. In peppermint, the essential oil composition is typically 30-55% menthol and 14-32% menthone. Minor components of mint oil may include eucalyptol, carvone, pulegone, and d-limonene.

These plants evolved to produce these compounds for a very specific purpose. Like many other fragrant, oil-rich plants, mints use these oils to defend themselves and deter herbivores. By extracting the essential oil of these plants, we can harness the power of these natural compounds. The essential oil of mint has been widely studied as an insecticide and antimicrobial agent, and is effective against numerous pests and pathogens. Mint oil and its components are effective both as contact insecticides and as fumigants.

A photo of mint leaves. Image from Wikimedia.

Pest species which can be treated effectively with mint oil:

• Trialeurodes vaporariorum, the greenhouse whitefly

• Aphis fabae, the black bean aphid

• Macrosiphoniella sanborni, the Chrysanthemum aphid

• Myzus persicae, the green peach aphid

• Acyrthosiphon pisum, the pea aphid

• Plutella xylostella, the diamondback moth

• Chaetodactylus krombeini, Krombein’s hairy-footed pollen mite

• Tetranychus urticae, the red spider mite

• Sitophilus zeamais, the maize weevil

• Callosobruchus chinensis, the adzuki bean weevil

• Sitophilus oryzae, the rice weevil

• Tribolium castaneum, the red flour beetle

• Mayetiola destructor, the Hessian fly

• Acanthoscelides obtectus, the bean weevil

• Oryzaephilus surinamensis, the sawtoothed grain beetle

• Thrips tabaci, the onion thrips

• Musca domestica, the house fly

• Stomoxys calcitrans, the stable fly

• Bactrocera oleae, the olive fruit fly

• Drosophila melanogaster, the common fruit fly

• Spodoptera littoralis, the Egyptian cotton leafworm

• Spodoptera litura, the tobacco cutworm

• Callosobruchus maculatus, the cowpea weevil

• Various mites
• Various mosquito species
• And many others!

Beneficial species which may be affected by mint oil:

• Adalia bipunctata, the two-spotted ladybug

• Osmia cornifrons, the horn-faced bee

• Phytoseiulus persimilis