5 Reasons For White Spots On Mint Leaves [Causes & Treatment]

People are fond of mint for its aromatic fragrance and its health benefits. Whether it’s a cocktail or a fresh smoothie, mints always bring some extra freshness. 

They may forever seem green and bushy but they are not immune to diseases. Whites spots on the leaves are a very common problem of mint and your mint plants need your help to overcome this problem. 

Now you might be wondering – How do you get rid of white spots on my mint leaves? 

Well, to get rid of the whites spots, diagnosing the right problem is very important. Otherwise, the white spots will only keep increasing.

Don’t you worry! In this article, I’m going to explain what the causes are behind these white spots and how to treat them. 

Fungal Problems, Viral Attacks, Pest Infestation, Nutrient Deficiency and, Incorrect Watering are the 5 major reasons that can cause white spots on your mint leaves

So without making any delay let’s jump right in-

How To Get Rid Of White Spots On Mint Leaves?

1.Fungal Disease of Mint

Fungal diseases are the first thing that causes white spots on mint leaves. Mints are even more prone to different fungal diseases than other plants. Powdery mildew, White mint rust, Sclerotinia Rot are the three major fungal problems that make white little spots on the mints. 

Powdery mildew is a very noxious disease of mint. It occurs very frequently in wet and humid weather where the temperature ranges from 10-25° C. The mint leaves get white fuzzy spots on the upper side. It seems like the leaves are dusted with powder. Powdery mildew infection usually starts first with the lower leaves. 

The earlier you get rid of these white spots the better it is for the mint plant. Because as the disease progresses the leaves can start to twist and disfigure. It can even attack the stems and cover the entire plant with white powdery substances.

In the case of white mint rust, small, white, and slightly raised spots are seen. It’s almost like the regular rust, except they have white spots instead of black. White rust also prefers high humidity like powdery mildew.

The fungus responsible for white rust grows inside the leaf layers. So this is why the white spots are a bit raised. Sometimes black and white spots can be seen at the same time on the mint leaves

Sclerotinia Rot is caused by a fungus called Sclerotinia sclerotiorum. It’s also called white mold. It appears as a cottony white fungus growth on the stems and leaves of mint. The stems have brown lesions. This disease ends up wilting the entire plant. 

Control Measures

Treat the fungus on your mint leaves as soon as you notice. Because we eat the mint leaves straight from the plants, so, we cannot apply any fungicide. Apply a safe and organic fungicide on them (our pick: Bonide Copper Fungicide).

Follow the label directions carefully while spraying. Keep applying the fungicide at one or two-week intervals until the problem stops.

Check out some of these easy and practical homemade recipes I’ve added below that can help you fix the white spots on your mint leaves naturally:

#Recipe 1:- Milk Spray Recipe

Ingredients:

  • 100 ml of milk
  • 1 liter of water

Steps:

  • Add them into the sprayer and give a good shake. 
  • Spray this solution on the affected mint leaves every week.

#Recipe 2:- Copper Spray Recipe

Ingredients:

  • 2.5 liters of water
  • 25 ml of copper sulfate
  • 5 tablespoons of hydrated lime (Calcium hydroxide)

Steps:

  • Add water and hydrated lime in a plastic container. avoid using any metal container because these ingredients can react with metal.
  • Continue to stir the mixture with a plastic spoon because the lime sets easily in the water
  • While stirring, start adding the copper sulfate into the container.
  • Shake the mixture very well before spraying. This mixture settles down easily so before spraying give it a good shake. 
  • Also while spraying, keep shaking the sprayer at intervals.
  • After spraying, wash the sprayer thoroughly because this mixture is corrosive.
  • Always use a freshly prepared mixture. Don’t store it for future use.

Recipe 3:- Baking Soda Recipe

Ingredients:

  • 1 tablespoon of baking soda
  • 1 teaspoon of liquid dishwashing soap
  • 1 gallon of water

Steps:

  • Mix these ingredients and put them into the sprayer
  • Spray on both sides of the leaves and stems 
  • Do not store the leftover mixture. 
  • This recipe is known to be effective against fungal attacks. But it can also burn the leaves of the plant sometimes

Note: For any homemade recipes try a small amount of the mixture on a small area of the leaf and see the response. If it doesn’t suit then change the concentration by adding more water and try on a small area again.

Preventive Measures

Avoid overwatering your mints. While watering do not wet the leaves. Always water at the base of the plant

Proper plant spacing is one way to prevent fungal attacks. Plant your mints keeping at least one feet distance from one another.

2.Viral Attack On Mint

Mints are often attacked by many viruses. Mosaic virus is the one that produces small white spots in a ring-like pattern or mosaic-like pattern. The leaves also get wrinkled and curled. The growth of the plant also gets stunted. 

The mosaic virus is transmitted by many insect pests like aphids, whiteflies, and thrips. Sometimes humans can also transmit this disease to the plants unknowingly.

Control Measure

The mosaic virus has no cure so it is very hard to get rid of. The best way to start is by cutting off the infected leaves with garden tools. Dispose of the infected leaves carefully. 

Since insects are the carrier of this disease, always be careful about pest attacks. Apply insecticides on a regular basis. 

But beware of harmful chemicals present in the insecticide. Because the mint leaves are mostly consumed raw. Use a good organic insecticide that is safe to apply for eating the leaves.  (our pick: Monterey Garden Insect Spray)

Preventive Measures

Disinfect the garden tools before and after use to prevent further spreading of this disease. Use row covers (our pick: Agfabric Floating Row Cover) to prevent pest attacks. If you are growing mints in pots then re-pot in fresh soil.

If any other plant gets infected by the mosaic virus make sure it doesn’t come in contact with the rest of the plants. Avoid working in the garden when plants are wet.

In the case of severe infestation remove the plant and throw it in the garbage. This may seem harsh but it can help to protect your other plants.

3.Pest Infestation On Mint

Spider mites, Thrips, Whiteflies, Mealybugs are the pests behind white spots that sometimes look like silver patches on the mint. 

All these insects suck the nutrients out of the leaf and produce white spots where they feed.

Spider mites are very tiny but they make small webs on the leaves. So look out for webbing on the lower side of the leaves. Also, check if the soil is too dry as it attracts spider mites.

Thrips and Whiteflies are hard to notice as they fly from plant to plant. Only severe infestation makes these two pests noticeable.

Mealybug makes a trail of white dots or lines on the leaves. The females lay eggs on the leaves covered in white cottony cover. The eggs also look like white spots.

Control Measures

In the case of smaller infestations give a gentle spray of water on both sides of the leaves to wash them off. For larger infestations, you have to apply insecticide. But before picking any insecticide you have to make sure it doesn’t create any toxicity in the mint leaves.

Get the best non-toxic organic insecticide for your mints so you can enjoy these fresh herbs anytime you like (our pick: Monterey Garden Insect Spray). Also, you can  try organic Neem oil or Insecticidal soap to control mint pests (our pick: Natria Insecticidal Soap)

I am adding some natural and effective home remedies that can fix pest problems. Don’t forget to try these out.

#Recipe 1:- Three-In-One Insect Spray Recipe

 Ingredients:

  • 1 small bulb of garlic
  • 1 small onion
  • 1 teaspoon of dry pepper powder
  • 1 tablespoon of liquid dishwashing soap

Steps:

  • Make a paste of garlic and onion in an electric blender.
  • Add the dry pepper powder to the paste. Then let it sit for a few hours or overnight.
  • Strain the mixture with a fine cloth and add the liquid soap and mix.
  • Add some water and make it a 2-liter solution.
  • Spray it on both sides of the leaves.
  • Be careful while handling the mixture because hot pepper in the solution can cause skin irritation. Use disposable plastic gloves while spraying. 

#Recipe 2:- Orange Spray Recipe

 Ingredients:

  • A large orange peel
  • 500 ml of water

Steps:

  • Boil water and remove it from heat.
  • Peel the orange and add the peels into the hot boiling water.
  • Cover with a lid so the orange peels can infuse with the water
  • Let it stay until the water cools down.
  • Remove the peels and spray the solution on both sides of the mint leaves.

Preventive Measures

As I’ve said before Spider mites thrive in dry conditions especially when the temperature goes above 85° F. In this case make sure there is enough moisture on the soil. 

Don’t use insecticide when the temperature is high. Because it can cause burning in the leaves. You can introduce some beneficial insects such as ladybugs, and lacewings. Because they feed on these pesky insects and also they don’t do any damage to the plant.

4.Nutrient Deficiency of Mint

Iron and Magnesium deficiency deficiencies can produce white spots on mint leaves. These two nutrients are important for photosynthesis. So when a plant lacks these two nutrients it cannot make enough food for itself. As a result, the green leaves start to become pale with white spots. 

Acidic soil may lack Magnesium and alkaline soil may indicate iron deficiency. Check your soil pH with a pH meter to determine the particular nutrient deficiency.(Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden)

If you don’t have a pH meter then try mixing a cup of baking soda, a cup of water into 4 tablespoons of the soil sample. If you see bubbles then the soil is likely to be acidic. But this is just a near assumption.

Control Measures

As we know, one nutrient deficiency can inhibit the uptake of another. So don’t forget to feed your mints with a good dose of the best slow-release mint fertilizer (our pick: Jobe’s Organics Herb Plant Food)

Also, Make sure you have a good drainage system so that the mints can absorb the nutrients thoroughly.

5.Incorrect Watering of Mint

If there are no signs of pests and fungal problems then your mints may be incorrectly watered. Overwatering and underwatering both can show white spots on the leaves.

Overwatering is more damaging in this case. Too much water blocks nutrient uptake so the leaves get white spots for lack of nutrients. Overwatering also encourages fungal diseases. 

Make sure you check the soil before watering with a moisture meter to avoid this fuss.

Control Measures

Mint plants don’t need serious watering. They only require one or two inches of water every week. Water them every week with good quality water. 

Avoid using hard water. Because hard water contains calcium and magnesium and creates an imbalance of nutrients in plants.

Frequently Asked Questions (FAQs)

Can I eat mint leaves with white spots?

Yes! As long as the white spots come from spider mites. But if the leaves have fungal growth or white powdery substance on them then you should not eat them. Smell the white-spotted mints, if they have a foul smell then the leaves are not edible.

Sometimes just some dust can look like white dots on your mint. You can wipe the leaves or give a good wash with lukewarm water and the spots will disappear. Then it’s okay to eat.

It’s best to treat the white-spotted plants first. You should not consume leaves with fungal infections. Because it can trigger allergic reactions in some people. And the leaves will also not taste good. They’ll be very bitter in taste.

Why are the white spots on my mint leaves increasing?

Even after starting to treat your plant you might see the white spots are still increasing. This means either the treatment is ineffective, or the diagnosis of the problem is wrong.

In this case, try to figure out what other causes can be the reason. This article will surely help you with that. You can try increasing the spray amount of the insecticide or fungicide.

But if the problem continues then get help from your local agricultural extension officer.

Can I eat mint leaves with brown spots?

If any fungal disease is causing brown spots then you shouldn’t eat them. But if water or heat stress is causing it then you can eat them after treating them properly.

Are all mints edible?

No! All types of mints are not safe to eat. Some are grown for consumption and some others are totally decorative plants. The edible ones have a strong wintergreen aroma. Spearmint, Peppermint, Apple Mint, Pineapple mints, Orange mints, Chocolate mints, etc are edible type mints.

Conclusion

I’ve tried my best to make this article as resourceful as possible. I hope you find the reason behind your white spots on mint leaves with their solutions. 

Now it’s time for you to figure out the problems and get down to work to fix them. Let me know if you have any more questions about this in the comments below. I will get back with the answer

I really hope this article helped you to fix the white spots on your mints. Cheer up your day with a mint cocktail with your very own grown mints. Best of luck.

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