Mint Leaf Beetles — Chrysolina herbacea — Chrysolina menthastri — UK Safari

For Anyone Interested in the Wildlife of the U.K.

Mint Leaf Beetles

Scientific name: Chrysolina herbacea (formerly Chrysolina menthastri)

Size: Up to 10mm long

Distribution: Found mainly in the south and up to the Midlands of England and Wales. A few sightings in Scotland

Months seen: May to September

Life span: Just over 1 year

Habitat: Gardens, damp meadows and riversides

Special features: The mint leaf beetle, as the name suggests can normally be found in the summer months munching away at the leaves of various mint plants. Its whole body is a jewel-like iridescent green colour which is peppered with tiny little indentaions. Both the larvae and the adult beetles feed on mint.

There is another similar looking species which also feeds on mint, but is an iridescent blue colour. As you might expect it’s called the Blue Mint Beetle (Chrysolina coerulans)


2012 — Sherborne, Gloucestershire — G. Bradley
2014 — Caithness — Margaret Bruce
2015 — Cheltenham, Gloucstershire — Alice Boston
2017 — Sibford Ferris, Oxfordshire — Carole Dean

Mint leaf beetle

Mint leaf beetles may feast on your garden mint — learn how you can get rid of them.

A table displaying which months are best to sow, plant and harvest.

Do not Time to act in January

Do not Time to act in February

Do not Time to act in March

Do not Time to act in April

Do Time to act in May

Do Time to act in June

Do Time to act in July

Do Time to act in August

Do Time to act in September

Do not Time to act in October

Do not Time to act in November

Do not Time to act in December

The mint leaf beetle, Chrysolina herbacea is a native, iridescent green beetle that feeds on the leaves of the mint family in the south of the UK. Both the adults and their fat, black larvae feast on the foliage.


Holes in leaves, made by iridescent green beetles and their and fat, black grubs.

Find it on


Mint is a prolific plant, so there’s no need to control the beetles. If you’re worried, you could try growing pennyroyal, Mentha pulegium as a sacrificial crop, or simply remove beetles and larvae by hand and squish them. You could also spray with organic pesticides based on pyrethrum in spring and summer.

Rosemary beetle

Prevent damage to your herbs by adult and juvenile rosemary beetles.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Time to act
Time to act
A table displaying which months are best to sow, plant and harvest.

Do not Time to act in January

Do not Time to act in February

Do not Time to act in March

Do not Time to act in April

Do not Time to act in May

Do not Time to act in June

Do not Time to act in July

Do Time to act in August

Do Time to act in September

Do Time to act in October

Do Time to act in November

Do not Time to act in December

Purple-striped green beetles, 8mm long, congregate among the leaves, which they feed on. The beetles lay elongated eggs beneath rosemary leaves from September and continue to do so on warm days right through winter. These hatch after a couple of weeks and the larvae feed on the plants for about three weeks before entering the soil to pupate. Two weeks later the adults emerge and continue munching through the leaves and laying their eggs.


Holes in leaves and tiny elongated eggs left by 8mm-long green beetles with purple stripes.

Find it on

rosemary, lavender, sage, Russian sage, thyme


Pick off the adult beetles and larvae by hand and destroy.


Spray with an insecticide, thiocloprid, between late summer and spring. Avoid using insecticide when the plants are in flower as bees may also be killed.

Mint Leaf Beetle — Chrysolina herbacea

Up to 10 mm long. The whole body is an iridescent green colour and peppered with tiny indentations.

Nearly always found on mint.

Peak time seems to be August and September.

Both the larvae and the adult beetles feed on mint.

Found mainly in the south and up to the Midlands of England and Wales. A few sightings in Scotland.

Uncommon or under recorded in Leicestershire and Rutland. It was not recorded in our area until 2016.

Leicestershire & Rutland Map

Enter a town or village to see local records


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

Leaf beetle

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Time to act
Time to act
Leaf beetles
Scarlet lily beetle Lilioceris lilii in Oxfordshire, UK
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Chrysomeloidea
Family: Chrysomelidae
Latreille, 1802 [1]

Leaf beetles are the family Chrysomelidae. There are over 35,000 species in more than 2,500 genera, so it is one of the largest and most common of all beetle families. Many subfamilies are recognized.

Leaf beetles have a tarsal formula which appears to be 4-4-4, but is actually 5-5-5. [2] Some are difficult to tell from long-horned beetles (family Cerambycidae): it is done by the antennae not arising from frontal tubercles.

Adult and larval leaf beetles feed on all sorts of plant tissue. Their diversity has run parallel with that of the Angiosperms. [3] Many are serious pests of cultivated plants, for example the Colorado potato beetle (Leptinotarsa decemlineata), the asparagus beetle (Crioceris asparagi), the cereal leaf beetle (Oulema melanopus), and various flea beetles. A few act as vectors of plant diseases. Others can be used as biocontrol of invasive weeds. Most Chrysomelidae are conspicuously coloured, often in glossy yellow to red or metallic blue-green hues. Some (especially Cassidinae) have spectacularly bizarre shapes. They are highly popular among insect collectors.


Selection of notable sub-families:

  • SubfamilyBruchinae – includes the bean weevils or seed beetles. They feed on seeds, some even on toxic seeds.
  • SubfamilyCassidinae – includes the tortoise beetles and prickly leaf beetles. A recent offshoot of the Hispanae.
  • SubfamilyChrysomelinae – includes the broad-bodied leaf beetles. «They defend themselves with a pot-pourri of toxins». [3]
  • SubfamilyCriocerinae – includes the asparagus beetles and lily beetles
  • SubfamilyCryptocephalinae – includes cylindrical leaf beetles and warty leaf beetle. «The larvae eat dead leaves and carry a protective case made of faecal and debris particles». [3]
  • SubfamilyDonaciinae – includes the longhorned leaf beetles
  • SubfamilyEumolpinae – includes the oval leaf beetles
  • SubfamilyGalerucinae – includes the flea beetles. The former subfamily Altricinae is included.
  • SubfamilyHispanae – many are leaf miners.
  • SubfamilySagrinae – frog-legged beetles or kangaroo beetles, diverse in Australia. «They have spiny hind legs built like nutcrackers that grasp and impale attackers». [3]


Records from the Cretaceous period are scarce: only three records are known. [3] An early Cretaceous origin from a more general form is suggested by Grimaldi and Engel. [3] Then came an Upper Cretaceous divergence of Chrysolmelid sub-groups, and adaptive radiation connected to that of the flowering plants. [3]

For Anyone Interested in the Wildlife of the U.K.

Blue Mint Leaf Beetles

Scientific name: Chrysolina coerulans

Size: Up to 10mm long

Distribution: A few sightings in Kent and Cambridgeshire in England

Months seen: May to September

Life span: Just over 1 year

Habitat: Gardens, damp meadows and riversides

Special features: Blue Mint Beetles are thought to have arrived in the UK from mainland Europe around 2011. As the name suggests they are normally found on the leaves of various mint plants. Their whole body is an iridescent blue colour which is peppered with tiny little indentaions. Both the larvae and the adult beetles feed on mint.

There is another similar beetle which also feeds on mint, but is green in colour. It’s called the Mint Leaf Beetle (Chrysolina herbacea)

Mint Pests: Identification and Removal

Zach has been an online writer for over seven years. His writing focuses on gardening, cooking, and aquariums.

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.

Spider Mites

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.

Flea Beetles

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.

Final Word

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.


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Margaret DePass

Thanks so much for this info, I will try it. My leave are curled in the center and it does look some parts black some parts paled out. Ive used horticultural corn meal which I saw on a show as an all natural pesticide and it works but if I forget for 1 month to shake it on the leaves the pests are back. It also doesn’t stay on the leaves and wind blows it off so i will try some of your natural remedies here. Thanks again.

Judy pascoe

Something is eating my herbs especially coriander and sage which i cant seem to find what’s the likely pest to attack it and how to treat it naturally

Shawn Freeman

My spearmint plant is like a month old, growing quite well, but over the past week i began noticing my leaves we’re being eaten, they start as holes or parts of the leaf, but eventually they eat whole leaves, leaving the center vein of the leaf intact

I do not know which pest it might be, I don’t see any of the pests spoken of


Thank you for this article. It really gave me insight on how to save my plant. I have some of the plant left to save. I was wiped out last year, now I’m armed with info. I thought mint kept most pests away. Now I know.


very informative article.

thanks for sharing,i learned a lot


Very helpful article. Thank you! I just found spider mites on my mint plant and hopefully I get rid of them soon. Or maybe as much as possible. I like using my mint for fresh mint tea.

Deborah Austin

Cats love mint and will eat the leaves off a plant


Thanks I learned a lot

E Croker [email protected]

Thankyou for your help I did have spider mites & loopers now there is a very small green thing about 1/2 cent long like a small grass hopper but a lot softer with no big legs hope you can help.


Thank you! I lost all my mint this spring and now my new plant has loopers. Now I know not to panic. This spring I had only a few tiny sprouts when I would normally have many new. When I dug out the pot I found an infestion of hundreds of white grub-looking invaders. They were very white and about 3/8 to 1/2″ long. What are they? What can I do to avoid them next spring?


8 years ago from Colorado

RTalloni — No problem! The season is right around the corner, so I figured I start sharing! Do you keep ample space between mint varieties to prevent cross pollination?


Thanks for this info on mint pests. We like to grow different varieties and dry them to make teas, but we only use undamaged leaves. This will be helpful.

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