black friday deals

What is the White Stuff on Lemon Tree Leaves? Know Now!

Growing a plant or tree without facing any problem is a dream of every grower and farmer. During the crop life cycle, different diseases and insects attack the tree. The same goes with citrus species cultivation. If you grow lemon trees, then you must have observed some white stuff on the leaves. But what is this White Stuff on Lemon Tree Leaves?

Moreover, Is it damaging to the trees, or is it harmless? Don’t go anywhere because we are answering your questions here in this Article!

As a Bonus, there is a FAQs section in which we have addressed the most asked questions related to lemon leaves problems.

What is the White Stuff on Lemon Tree Leaves?

White Stuff on Lemon Tree Leaves may be insects or fungus attacks. Lemon tree pests and diseases are both responsible for the poor quality of the fruit. But what causes white spots on lemon tree leaves?

Let’s have a look at the possible reasons for the white stuff on lemon tree leaves.

Powdery Mildew

If you are wondering what is the white stuff on my tree leaves, then let us tell you this can be Powdery Mildew (A fungal disease in which white spots are formed). But What causes Powdery mildew?

Powdery Mildew is caused by Fungi Odium Citri, and O. tingitaninum. This disease occurs if the surrounding is shady and air circulation is less.

Powdery Mildew forms tiny whitish or grayish spots. Initially, these spots are formed on top of the leaves. Then these spots can also be formed on the stems, flowers, and buds.

The spots on the leaves affect photosynthesis which leads to leaf dropping off. Moreover, a low photosynthesis rate means plants/trees are producing less food (which is Glucose).

So, Due to powdery mildew, the lemon tree will show:

  • Low productivity
  • Poor fruit quality as white powdery spores appears on fruit.

If such spots are formed on the florals, then they don’t bloom. Twigs and branches are not safe from this disease and may die due to this disease as well.

People ask how do you treat white spots on lemon tree leaves? Well, know how you can treat powdery mildew!

How to get rid of powdery mildew on lemon tree?

If you observe the powdery mildew is affecting your lemon tree, then start the treatment immediately. Want to know how to treat white fungus on a lemon tree? Well, You can apply the following treatments on the infected lemon tree parts:

Baking Soda

It is an excellent lemon tree white fungus treatment. You can make a baking soda solution to get rid of powdery mildew. All you have to do is mix 1 tablespoon of baking soda in a gallon of water. Then, add half a tablespoon of liquid soap to the mixture and stir. Pour this solution into the spray bottle and spray the solution directly on the white spots on lime tree leaves. You can also spray Baking soda solution as a preventive measure too.

Potassium BiCarbonate

You can also make a Potassium BiCarbonate solution to treat Powdery Mildew. To make this, mix 1 tablespoon of Potassium BiCarbonate in a Gallon of water. Then, add half a tablespoon of liquid soap to the mixture. Stir this solution thoroughly and pour it into a spray bottle.

Spray this solution on the leaves’ top, bottom, and other infected parts of the lemon tree. According to some, this solution is better than the baking soda solution.

Neem Oil

Neem Oil is another extract that is super effective against powdery mildew. You can make a solution of neem oil and add it into other treatments (such as Baking Soda, and Potassium BiCarbonate) to increase their effectiveness.

It is also recommended to reapply any fungicidal treatment after every 14 days.

After knowing how to treat white fungus on Lemon Tree, it is time to know about some preventive measures too.

Preventive measures

According to Colorado State University, Fungicide works best with preventive measures.

1) The best preventive measure of Powdery Mildew is to grow powdery mildew-resistant varieties. Such plants or trees don’t face the problem of fungi and you can save a lot of money when you buy such cultivars.

2) Remove any infected part of the tree before the application of fungicide.

3) Another preventive measure is to Get rid of susceptible trees. Generally, they are being grown in the shade and have wet surroundings.

4) Make sure your trees have enough distance between them. Enough space leads to better air circulation which reduces the chance of powdery mildew occurrence.

5) Make sure the soil you are using has better drainage properties. As powdery mildew fungi love moisture, if the drainage is poor, then the chances of its attack increase.

6) It is important for you not to overfertilize trees. Excessive fertilization leads to lush green leaves which attract pathogens and insects.

People ask, there is white stuff on my fruit trees, what did I do wrong? Well, if you follow the precautions described above, then this situation will not come!

White Stuff on Lemon Tree Leaves and fruits.
Infected Lemon Fruit

Bleach spots on lemon tree leaves are formed due to insect infestation. Lemon tree pests and diseases are both responsible for


MealyBug is another insect that troubles citrus species. They can be the White Stuff on Lemon Tree Leaves you are observing. They’re present on the stem, bark, and leaves of the plant/tree where they appear as white cottony masses.

MealyBug sucks the juice present inside the lemon tree. This unable the tree to move nutrients and moisture inside to other parts of the tree. Moreover, due to the sucking, honeydew “emerges” on the leaves which makes them sticky.

Thus, trees get deformed and look weak due to mealybug infestation. Furthermore, due to mealybugs, white sticky stuff on lemon tree leaves gives the tree an unpleasant appearance. This is the answer to your question, why are lemon tree leaves sticky?

White Stuff on Lemon Tree Leaves
Mealy Bugs

How to get rid of mealybugs?

Want to know how to treat white sticky stuff on plants or trees? Well, You can do the following things to get rid of MealyBugs:


You can make an effective insecticide to treat mealybug at home. First of all, take cotton balls and swabs. Dip them into alcohol and remove the visible mealybugs with them.

Then, mix a few drops of liquid soap into a cup of rubbing alcohol. Add this mixture into one quart of water and keep stirring. In the next step, Pour the solution into a spray bottle and spray it onto the affected parts.

You can also use neem oil solution to get rid of mealybug infestation. All you have to do is mix one ounce of neem oil in a gallon of water and spray it on the affected parts. Reapply this solution after two weeks again for better results.

Use of Beneficial Insects

You can control the mealybug population by releasing beneficial insects. Ladybird beetles, lacewings, and mealybug destroyers are those insects that you should see as friends.

Preventive Measures

As we have mentioned above, do not over-feed plants or trees. Applying too many fertilizers in large quantities will cause leaves to appear lush green. These leaves attract insects like mealybugs.

Moreover, do not let the weeds grow near the lemon tree. These weeds can become a host of dangerous insects.

Citrus Snow Scale

Usually, a citrus snow scale is present on the lemon tree trunk. However, if their infestation is severe, these insects can also be present on the leaves and other parts of the tree. But why these insects are dangerous to your lemon tree? These insects drink the sap which leads to nutrient deficiency in trees. Moreover, these insects reproduce quickly which is another major cause of concern. Since they are white, thus, these might be that White Stuff on Lemon Tree Leaves you are observing.

Snow Scale’s Females insert their mouthparts in the trunk or leaves and stay there to suck the juice. Immature males also do the same until they develop the wings.  

Due to their vigorous feeding, the branch or trunk of the tree splits. This splitting is an open invitation for the fungi and pathogens to attack. Moreover, leaves die off too due to their attack.

How to get rid of Citrus snow scale?

Getting rid of the citrus snow scale is hectic as these insects pile upon one another which makes the application of control measures difficult. You can try to kill these insects by following measures:


To get rid of citrus snow scale, first, brush off some of the insects from the layer or pile they have formed. Then, you can apply both organic and chemical insecticides. Generally, two insecticides are used to curb their population:

1) You can mix baby oil and rubbing alcohol to make an insecticidal solution. All you have to do is mix and then apply to the insects’ population.

2) You can also use white oil to get rid of snow scales. All you have to do is mix two cups of vegetable oil into a half cup of liquid soap. Pour it in a bottle or jar and shake vigorously. Then add 20 ml of this solution into a liter of water. After that, pour this solution into a spray bottle and apply it to the infected area. This solution is also effective against aphids and other garden pests. If you are a gardener, then you must have white oil in your cabin.

Beneficial Insects

You can also use beneficial insects to get the population of citrus scale in control. Parasitic wasp Aphytis lingnanensis and ladybird bottle eat snow scale which reduces their population.

Preventive measures

Following are the preventions you can opt for to avoid citrus snow scale infestation:

1) Do not add fertilizers in excess. This leads to lush green leaves which attract insects like citrus snow scale.

2) Clean your gardening tools every time you use them. Sometimes, insects like citrus snow scale travel from one place to another on these tools.

There is another insect called Cottony Cushy Scale. It is responsible for white spots on Orange Tree Trunk. But this does not greatly impact the lemon leaves and trunk. Did you know that there is a fruit which is a cross of lemon and orange? Well, it is called the Meyer Lemon tree and the Cottony cushy scale affects this crossed tree as well. Moreover, Meyer lemon tree diseases include root rot, greasy spot, foot rot, etc.

Final Words

All-inclusive, a grower faces a lot of problems during growing a plant or tree. Lemon trees are no exception as well. While cultivating lemon, you may observe some irregularities. You may start seeing some whiteness on the leaves after some time of growth. You should take this White Stuff on Lemon Tree Leaves seriously as these may be a fungi attack or insect infestation. Start the treatment immediately which we have described above in this article. Why? Because it is in your best interest to get rid of them as quickly as possible for better fruit quality and yield.


How do you get rid of powdery mildew on citrus trees?

You can get rid of powdery mildew on citrus trees by applying Neem oil solution, baking soda solution, and Potassium BiCarbonate solution.

Why is my lemon tree leaves turning white?

Your lemon tree leaves are turning white due to a fungi attack. Fungi cause a disease known as Powdery Mildew which appears whitish on the leaves. That is why, if your lemon tree has white stuff on leaves, then this might be powdery mildew.

How do you get rid of the citrus snow scale?

You can get rid of the citrus snow scale by using neem oil, or by a solution made up of baby oil, rubbing alcohol, and water. Moreover, beneficial insects also control the population of these insects.

Related Topics:

I am a graduate in Agriculture Sciences and have been doing gardening for over 7 years. I am also a professional and certified Article & Blog Writer. I am happy to share my years of experience in gardening with all of you through my writings. In addition to this, I do extensive research on every topic to enrich readers with valuable knowledge.