Mint plants have been used by gardeners to help keep pests such as mice, flies, moths, ants and mosquitoes away. It's ironic, therefore, that mint itself is susceptible to garden pests. Mint can be used for a variety of different things, but if your mint plants get attacked or eaten you won't be using them for anything.
European Corn Borer
The European corn borer is a moth known to do damage to the mint plant. When in the larval stage, European corn borers eat away at the plant, damaging the stability of the stalks and cutting off the vital delivery of crucial nutrients to certain parts of the plant. In rare cases, European corn borers have also spread disease to plants they infect, so taking care of them at the first sign of infection is crucial to the health and safety of your mint crop.
Loopers are called so because of the way they walk in their larval stage due to the way their bodies work. A common mint pest, loopers usually attack mint plants from May to July, sometimes later depending on the weather. The larvae look like little green caterpillars and the full-grown looper is a type of moth. The females are usually light brown, and the males get to be darker brown in color.
Another common mint plant pest, cutworms feed on mint plants both above and below ground. Above ground they are known to eat the foliage produced by the mint plant, and below the surface, they typically eat through stems, causing great damage to the mint plant. Though there are many different kinds of cutworms, the most common variety are identifiable by a "V" shaped pattern on their back, and they are usually brown, green or creamy in coloration.
Two-Spotted Spider Mites
Two-spotted spider mites, though hard to see, can cause serious damage to your mint plant. Though they can be too hard to see unless you're specifically looking for them, it's not hard to tell when they are infecting your mint plant. Usually found on the underside of the leaves, two-spotted spider mites break through the skin of the foliage with their mouth and suck out vital nutrients, which wither the plant and leave leaf matter yellow or brown. A common notifier of a two-spotted spider mite infestation is webbing. All spider mites create small webs on the plant visible to the naked eye. It is absolutely vital to the survival and well being of your mint plant that you control spider mite population at the first sign of infection because of how quickly spider mite populations can grow out of control.