Mint Pests: Identification and Removal
Mint is the garden herb that's practically a pest itself. With the ability to thrive in less than desirable conditions, mint is best known for its ability to establish itself quickly and spread fast. If left uncontrolled, mint will take over garden beds and suppress the growth of competing plants.
With its fast growth and hardy nature, it may come as a surprise to hear that there are several pests that can really set this plant back. So, if your mint is growing slow or seems less than exuberant, it might be that a pest is behind the problem. This article will cover the proper identification and natural removal of common mint pests.
List of Potential Mint Pests
Here is a list of potential mint pests with some telltale signs that they are damaging your plants.
- Spider Mites: Leaves speckled with yellow spots & thin webbing.
- Loopers: Missing or large holes in foliage.
- Flea Beetles: Clusters of small holes in foliage.
- Aphids: Small winged & wingless insects on leaves.
- Cutworms: Cut at the stem or dead plant.
- Thrips: Curled or distorted leaves.
The mite associated with causing mint damage is the Two-Spotted Spider Mite. These small (~3-4 mm) translucent-colored pests live on the undersides of mint leaves and generally cluster towards the top of new growths. Thriving in hot and arid conditions, spider mites cause damage by piercing tiny holes in leaf cells. They'll make their presence known by causing speckled discoloration on leaves and leaving behind a thin webbing that is much like a spider's.
How to Get Rid of Spider Mites
- A blast of water can diapers these pests.
- Use a plant-based insecticide, such as pyrethrum or rosemary oil. These can kill the mites without harming the plant or other creatures. Other organic treatments include garlic water and hydrogen peroxide.
- Apply potassium salts to your plants. These are quite abrasive against spider mites.
- You can introduce beneficial insects that prey on spider mites, such as ladybugs.
- Wipe your plants down with rubbing alcohol. This can kill the mites.
Both the Alfalfa and Cabbage Looper are pests of the mint plant, with the latter being the more common of the two. Loopers are foliage-consuming caterpillars that reach 1–2 inches in length and are normally varying shades of green. They cause significant damage by consuming large portions of leaves and stems. Instead of being called a caterpillar or worm, loopers get their name from their unique 'curling' or 'looping' movement.
How to Get Rid of Looper Worms
- If the amount of worms is relatively small, you may just be able to pick them by hand.
- You can use bacillus thuringiensis, which is an organic compound that can kill the worms without harming other animals. You'll have to trim the mint to the ground prior to spraying.
Mint plants suffering from flea beetles are easily spotted, as the beetles will jump from the plant's leaves when disturbed. These small (~1.5 cm) beetles are a shiny black/bronze color. They cause damage by chewing small holes through the leaves. These holes will often show up in clusters.
How to Get Rid of Flea Beetles
- Create a mixture of two cups of rubbing alcohol, five cups of water, and one tablespoon of liquid soap. Spray the mixture on your plants to keep flea beetles away.
- Dust your plants with talcum powder.
- Placing sticky traps near your plants can capture flea beetles.
- Spray your leaves with neem oil.
- Apply diatomaceous earth near your plants. It kills flea beetles when they crawl over the powder. Since seedlings are most effected by flea beetles, it is wise to cover them until they have established.
These small insects like to attack the leaves of plants and suck out their sap. A sign of aphids is when your plant leaves begin to curl and turn yellow. You may also notice a sooty mold on your plants. This is the result of aphids secreting honeydew.
How to Get Rid of Aphids
- If there are only a few insects on your plants, you can try pruning the leaves they are one.
- Spraying water may be effective if the number of insects is small.
- Reflective mulches can deter some aphids. Something bright and shiny in color can keep them away.
- A light infestation can be handled by spraying a mixture of water and dish soap. You can mix a quart of water with a few teaspoons of dish soap.
- Insecticide may be need if there is a heavy infestation. Look for insecticides with imidacloprid. This will kill aphids without harming other beneficial insects like bees and butterflies.
Cutworms of the larvae of various species of moths. They are found in the soil and feed on the stems of plants. You may have cutworms if you see seedlings have been severed at the soil line. If damage is not visible at the stem, you may notice your plants shrivel and die.
How to Get Rid of Cutworms
- If the infestation is small, you may be able to pick out the cutworms. They usually come out at nigh. Drop them into soapy water to kill them.
- Surround your plants with diatomaceous earth. This will kill the cutworms when they walk over the powder.
- You can use an insecticide like bacillus thuringiensis. It would be best to apply it in the afternoon, before the cutworms come out at night.
Thrips are small flying insects that eat various plants. They puncture plants and suck out their contents. They can potentially spread diseases to plants. A sign to their presence is the curling or distortion of leaves.
How to Get Rid of Thrips
- Sticky traps can help capture adult specimens.
- Spraying water can help dissuade infestations from damaging your plants.
- Releasing beneficial species like ladybugs and pirate bugs can help. These species prey on thrips.
- Botanical insecticides like pyrethrin can help reduce thrip populations.
Of all the possible pests to feed off of mint, spider mites are the most serious. If a mint plant is infected with spider mites, a quick course of action should be followed. Loopers and flea beetles are really only an issue for seedlings and young mint plants. Thank you for reading my article on mint pests. Please leave any comments, questions, or suggestions that you may have.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.