How to Get Rid of Brown Spots on Basil?[Causes &Treatment]

Basil leaves have healing and healthful properties for humans. They are good for digestion, skin, depression, diabetes, blood flow, eyesight, and immunity. So, gardeners love to grow basil. But the saddest thing is brown spots on basil leaves.

You are here means you are in the same problem. Don’t worry, you are not alone. Because the brown spots are the biggest problem that every basil growers face.

Fungal infestation, insects, bacterial diseases, and cultural activities can be the reason for brown spots. So, you should know every possible reason to take effective steps.

And in this article, I have covered every detail about brown spots on basil leaves with the most effective solutions.

So, without losing your valuable time, let’s get started-

Causes and Treatment of Brown Spots on Basil

1.Bacterial Leaf Spot on Basil

Bacterial leaf spot (BLS) is the most common problem for basil that can create brown spots on basil. Besides basil, it is also destructive for peppers, tomatoes, and other vegetables. It is caused by the gram-negative bacteria Pseudomonas cichorii.

You should know how this disease develops and spreads?

The bacterial leaf spot develops only when you splash water on your basil plant in humid and warm weather. After that, the pathogen spreads from affected leaves to healthy plants and leaves by your hand and dirty tools.


Round and irregular shaped and water-soaked spots appear and the spots turn brown in color. The bacteria can affect the stems too. You can notice black and brown spots on the basil stem.

Controlling Measures

You should first stop spreading the pathogen. So, remove the affected leaves more carefully. Removing affected leaves also increases the air circulation that also helps to control the disease.

Now apply the copper-based organic fungicide or Bacillus subtilis containing bio fungicide to control and treat the bacterial leaf spots of basil. Here is the recommended fungicide that works great to kill bacteria and fungus- Serenade Garden AGRSER32 or Southern Ag – Liquid Copper Fungicide.

And prevent the disease, never apply water overhead, and don’t use dirty tools.

2.Downy Mildew of Basil

Downy Mildew is a fungal disease that is caused by Plasmopara viticola. This fungus spread by air more rapidly. So, you should take action without delay.

Like all other fungal diseases, it also develops in wet and cold weather. At first, pale green to yellow spots appear on the basil leaves and later the spots turn brown. Also, the grey fuzz forms on the underneath of the leaves. 

If you notice brown spots on basil and mint leaves after rain and cold weather, then there is enough chance to happen it by Downy mildew or other fungi.

Controlling Measures

Remove the affected leaves carefully and spray a fungicide that contains copper, mancozeb, and Bacillus subtilis fungicide. You can pick Serenade Garden AGRSER32 or Southern Ag – Liquid Copper Fungicide to control both downy mildew and bacterial leaf spots.

3.Other Fungal Diseases

Without downy mildew, some other fungal diseases can develop brown spots on the basil leaves. Fungal leaf spots, Cercospora Leaf Spot, and Fusarium Wilt are the fungal diseases that can make small to big brown spots on basil.

Fungal leaf spots

Colletotrichum fungus is the causal organism of the Fungal leaf spots. At the primary stage, It shows black to brown spots on the basil. Then the spots dry the plant cell and create holes on basil leaves.

Cercospora Leaf Spots

Cercospora Leaf Spots is another devastating foliar disease of basil that is caused by Cercospora beticola. As the symptoms of the diseases, the basil leaves show tan to light brown color circular spots with reddish-purple borders.

Fusarium Wilt

Fusarium oxysporum fungus is the causal organism of the Fusarium Wilt. This fungus works on the basil vascular tissues and destroys them. As a result, the plant can’t transport water and the basil stems turn brown and brown patches appear on the basil leaves.

Controlling Measures

Apply copper-based organic fungicide, Bacillus subtilis containing bio fungicide, or tebuconazole containing an inorganic fungicide to control the fungal diseases of basil. You can pick any fungicide from my recommendations. Our Picks-  Serenade Garden AGRSER32 or Southern Ag – Liquid Copper Fungicide.

To prevent the development of fungal diseases, never spray water mist on the leaves of basil. Apply the water just on the base of the basils. And remove the extra leaves that the air circulates freely.

Note: You can control and stop developing new fungus by spraying fungicide but it can’t heal the affected leaves. So, remove the affected leaves first and spray fungicide as a preventive treatment. Also, read the label directions of fungicide to know the application time and dosages.

Frequently Asked Questions

Is it OK to eat basil with brown spots?

You can eat basil leaves with some brown spots. But before eating take your scissors and cut the spots off. But if the spots occupy the whole leaves, then don’t eat.

Though there is no harm to happen if you clean the brown leaves properly and eat.

Why do basil stems turn brown?

You know, there are several diseases such as bacterial leaf spots, downy mildew, and fusarium wilt some other fungal diseases are the reason for brown spots on the basil leaves. But the only fusarium wilt can turn the green stems into brown.


My basil has brown spots on the leaves and how can I revive my basil plant? This the most asked question from basil growers.

If you want a quick answer, then remove the affected leaves and spray fungicide. Here are my recommendations- Serenade Garden AGRSER32 or Southern Ag – Liquid Copper Fungicide.

But if you want to know what is the reasons behind it and why you should apply a fungicide to treat brown spots on leaves. Then read the article and you will get all the answers that help you to deal with the basil problems.

Lastly, don’t spray water on the basil leaves. Just pour water base on the plant. If you follow the rule, you can protect your basil from many diseases.

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