Aphids on Mint: 12 Tips for Effective Treatment & Prevention

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Infestation of aphids on mint in the garden.

Discovering aphids on mint leaves and stems is never a fun thing. But these little pests don’t have to spell the end of your garden-fresh mint in cooking and drinks.

There are several ways to effectively control aphids on mint plants:

  • Remove them by hand
  • Remove infested portions of the plant
  • Give the plant a thorough spray-down with water
  • Treat the plant with insecticidal soap or essential oils
  • If your treatment strategies don’t work, cuttings from healthy sections can be used to propagate a new mint plant.

I’ve experienced more problems with aphids than I care to recall in my gardening, so I know the feeling first-hand. In this post, I’ll share my best tips for dealing with an aphid problem and preventing infestations in the first plant. I consulted other gardening pros to get their expert insights as well.

So let’s get started and rid your mint plant of pesky aphids!

How To Tell If Your Mint has an Aphid Problem

Correctly diagnosing a plant problem can be tricky- several factors (water, light, disease, etc.) could be going on. Fortunately, figuring out whether your mint is suffering from aphids is fairly straightforward.

Aphid infestations generally present as a combination of:

  • Rumpled leaves- especially on new growth
  • Sticky substance on the leaves or surfaces below the leaves
  • Yellowish discoloration on leaves
  • Small green, white or black insects on leaf undersides, stems and growing points

Aphids have roundish, soft bodies with six legs. They may or may not have wings. They come in a variety of colors, but all aphids have a “tailpipe” or pointed cornicle on the back end.

Green aphids on a garden plant leaf.
Green aphids
Black aphids on a garden plant leaf.
Black aphids
Brown aphids on a garden plant leaf.
Brown aphids

Although they’re more common outdoors, aphids can also attack mint growing indoors. These little pests are sap-suckers. They use their sharp mouthparts to pierce plant tissue and drain its sap– think of them as “plant vampires.” This robs the plant of nutrients and hydration, causing a sickly appearance.

Aphids can also transmit several serious plant viruses that can wipe out your mint crop and other garden plants. Mosaic virus is the most well-known of these diseases, and it’s a problem that can last for years if it gets into the soil.

So it’s critical to keep a close eye out for aphids and treat the issue right away.

5 Ways to Get Rid of Aphids on Mint

Mint typically isn’t a first choice that aphids to attack first. But they do like things that flower, and mint has a long flowering season, even if you’re growing it indoors. 

Here are a few things you can combine to combat aphids on mint plants. For your greatest chances of success, combine two or more of these methods:

1. Manual Removal

Aphids don’t have strong legs to grip into plants, and they’re quite easy to wipe away by hand. I’ve removed aphids before with a cotton swab, and cotton balls, old rags and even just your fingers will work too.

Chris Chan, blogger at Garden Bench Top, says that manually removing aphids is helpful, there are drawbacks too. “While we do practice manually removing aphids from our mint plants, we’ve learned it is ineffective in the long term (unless of course, you don’t mind spending hours inspecting your mint). Aphids are exceptional at hiding, and all it takes is overlooking one and your mint will soon be infested again.”

So while it’s effective, manual removal works best with mint plants that have just a few aphids- usually at the very start of a problem. And if there’s one aphid, there’s likely to be more following- so check back on your mint plant several times.

2. Remove Severely Infected Leaves

If the aphids are confined to only part of the plant, remove it before the pests can spread. Also, if any areas are severely infested, you probably won’t be able to save them. So pinch off those sections.

Do not throw any pest-infested plant material into the compost- the pests can just spread from there. Instead, place the removed sections in a plastic bag and throw them in the trash, or dispose of the plant material by burning it.

3. Spray the Plant with Water

Aphids don’t have very strong limbs, and a hard stream of water will knock them right off the plant. Concentrate spray on growing points and leaf undersides: aphids like more hidden, sheltered spots.

  • For aphids on outdoor mint, reach for the hose for this task- but use a gentle stream of water to avoid harming the delicate mint leaves.
  • For aphids on indoor mint, take your plant to the shower for a spray-down.

But while a good washing will dislodge most aphids on the plant, a single treatment is not enough. Aphids have a roughly 4-week life cycle from egg to larva to adult. So spraying off the adults gets rid of that generation, but the eggs that are already there will hatch into a new generation.

The key here is to spray the plant down weekly for 4-5 weeks– that should break the life cycle.

4. Spray with Insecticidal Soap or Essential Oil

Insecticidal soaps and essential oils smother and burn the soft bodies of mature aphids.

Harshad Sawant, blogger at Indoor Mint, likes to use soapy water to combat aphids . “I spray the leaves down thoroughly, being sure to reach all of the nooks and crannies where the aphids might be hiding.” The soap dries out the aphids’ soft bodies, killing them quickly. Harshad adds, “Washing the plants with water will help remove any eggs or larvae that might be present.”

You can buy commercial insecticidal soap or make a homemade formula of 1 tablespoon of liquid castille soap to 4 cups of tap water. But be careful- some recipes call for dishwashing soap, which is actually a detergent that can harm your plants. Garden Fundamentals has a great video on the dangers of these recipes:

Essential oils can also work here. Add 10-20 drops of lavender, rosemary or tea tree essential oil to a spray bottle of water and spray the plant down. 

Just like with a plain water treatment, this will kill mature aphids, so you’ll need to spray weekly for about a month.

Before eating your fresh mint, be sure to rinse it to remove any residues.

5. Harvest Unaffected Plant Sections for Propagation

Sometimes, an infestation gets out of hand quickly, and none of your treatment strategies appear to be working.

At that point, it’s time to begin again. If there are any healthy sections left on the plant, cut them off to grow into a new plant. Luckily, mint is really easy to propagate even from a small cutting- I’ll show you exactly how in our post on propagating mint cuttings.

Fresh cut sprigs on mint.

7 Tips to Prevent Aphids on Mint

As with many things in life, prevention is the best cure when it comes to aphids. Here a few suggestions:

1. Introduce Beneficial Predatory Insects

Ladybugs are excellent aphid-eaters, especially in their larval form.

But instead of buying ladybugs, attract them to your garden by letting some leaf piles and perennial plant stalks stay in place through winter to provide shelter. Planting flowers that draw ladybugs is another helpful strategy.

  • Yarrow
  • Milkweed
  • Cosmos
  • Feverfew
  • Marigold

2. Remove Plants That Draw Aphids

Aphids are attracted to a wide variety of plants. They tend to like fruit trees and sticky flowers like calendula and peonies. And if you have some planted in your garden that always gets aphids every year, it might be a good idea to remove them.

Some gardeners take the opposite track and plant lots of calendula to act as a “trap plant.” The idea is that the aphids are going to come anyway, so planting calendula at least controls where they are in the garden. You can wait for the aphids to congregate on the calendula, then uproot it and throw it away, eliminating the aphid colony all at once.

3. Plant Companion Plants that Deter Aphids

Aphids avoid plants with strong scents and resinous oils, so plant a few of these around your garden as deterrents:

  • Chives
  • Cilantro
  • Garlic
  • Leeks
  • Basil
  • Lavender
  • Rosemary
  • Rue
  • Savory
  • Marigold

4. Don’t Overcrowd the Garden

Aphids are not strong fliers and they can’t move far on their small legs. So gardens that have lots of plants touching each other are more easily overtaken by aphids. Space your plants out to create airflow and buffer room in between, to make it harder for aphids to spread plant-to-plant.

5. Be Vigilant for Ants

Ants will actually farm aphids for their sticky honeydew excretions. They will herd the aphids onto a particular plant, bite off their wings so they can’t fly away, and protect them from predators like ladybugs and lacewings.

So large ant populations in your garden can sometimes lead to large aphid populations too. Keep an eye out, and use ant bait to control large ant populations.

6. Don’t Over-Fertilize

Over-fertilized plants have higher concentrations of nutrients and weaker cell walls than properly-fertilized plants. Plus, fertilizer encourages new plant growth, which is a favorite spot for aphids.

So when you fertilize, don’t exceed the dosage and application schedule indicated on the package.

7. Water Appropriately

A healthy, properly-watered plant is more resistant to pest damage of all kinds.

As a vigorous grower, mint likes quite a but of water, so aim to give your plant water whenever the soil feels dry 1 inch deep. The actual frequency will vary based on environmental conditions, so go by how the soil feels rather than on a strict watering schedule.

Aphids in particular like wet conditions, and a plant in soil that is always moist will be a potential target. So be careful not to overwater your mint and invite moisture-seeking aphids.

Infographic outlining how to treat and prevent aphids on mint.

Frequently Asked Questions about Aphids on Mint

While aphids don’t eat the actual leaf tissue, they suck out the sap from inside the leaves and stems, causing the affected areas to dry up and die.

Not really. If you catch an infestation before it really takes hold, you’ll be able to reduce their numbers so that they aren’t a problem. But heavy infestations are difficult to eradicate.

Final Thoughts

I’ve lost a few plants to aphids throughout my gardening experience, and it’s definitely a frustrating thing to deal with. Fortunately, if you catch the problem early, you can successfully manage the aphids problem and go on to have a delicious harvest.

And if you apply the prevention tips I listed, aphids may not be a big issue in future years!

I’d love to hear from you! Do you have any aphid-killing hacks? We learn best from one another, so please share your thoughts in the comments!

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