3 Reasons For White Spots On Crepe Myrtles [How to Treat] 

What can growers do when they see no flowers but only white spots all over the crepe myrtles? 

These white spots on the leaves and barks destroy the beauty of crepe myrtles. Also, the blooming is damaged drastically. There is no time to lose when you see these white spots if you want to see your crepe myrtles blushing with flowers. 

 So, what causes white spots on Crepe Myrtles? 

Powdery Mildew, Crepe Myrtle Bark scales (CMBS), and White Wood Rot – these three reasons are behind the white spots on crepe myrtles.

In this article, I am going to discuss these three reasons with all their easy solutions and preventions. 

So, let me walk you through them- 

Why are White Spots On Crepe Myrtles?

1.Powdery Mildew On Crepe Myrtles

Powdery mildew is a fungal disease of crepe myrtles. It creates white speckled powdery spots on the leaves, shoots, branches even in the flower buds. Infected parts of the plant become distorted and stunted. 

The white powdery substance covers the entire tree for severe conditions. Eventually, the leaves also start falling off.

Powdery mildew is very dangerous for crepe myrtles because it occurs during the late spring or early summer when evenings are cool but a little humid, while the days are starting to get warm.

And this is the exact time when crepe myrtles bloom. As a result, it damages the flower buds and the blooming is hampered badly.

Control Measure

The best way to control these white spots is to apply a fungicide thoroughly. Get the best fungicide that will not harm the flower buds (Our Pick: Bonide Copper Fungicide)

Water early in the morning in the base of the crepe myrtles. 

I am sharing some home remedies to get rid of the powdery mildew fungus from your crepe myrtles:

#Recipe 1:- Milk Spray Recipe

Ingredients:

  • 200 ml of sour milk
  • 2 liters of water

Steps:

  • Add the milk and water together 
  • Spray this solution with a sprayer.

#Recipe 2:- Copper Spray Recipe

Ingredients:

  • 5 liters of water
  • 50 ml of copper sulfate
  • 10 tablespoons of hydrated lime (Calcium hydroxide)

Steps:

  • Mix water and hydrated lime in a plastic container. Do not use any metal container because these ingredients are corrosive and they can react with metal.
  • Keep stirring the mixture with a plastic spoon because the lime sets easily in the water.
  • Continue to stir and start adding the copper sulfate into the container.
  • Now the solution is ready
  • This mixture settles down easily so before spraying give it a good shake. 
  • Also while spraying, keep shaking the sprayer at intervals.
  •  Wash the sprayer thoroughly after you finish spraying. Because this mixture is corrosive.
  • Always use a freshly prepared mixture. 
  • Don’t store it for future use.

Recipe 3:- Baking Soda Recipe

Ingredients:

  • 3 tablespoons of baking soda
  • 2 teaspoons of liquid dishwashing soap
  • 2 gallons of water

Steps:

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

Note:

Try these homemade recipes on a small area of the leaf first and see the response. If it doesn’t suit your crepe myrtles, then change the concentration by adding more water and try on a small area again.

Preventive Measure

Grow powdery mildew resistant varieties of crepe myrtles like ‘Tuscarora,’ ‘Tuskegee,’ ‘Wichita” Natchez” Glendora White’ etc. Get them six hours of direct sunlight every day and make sure they are planted in an airy location. 

Provide the right fertilizer and avoid over-fertilizing because powdery mildew thrives on new growth. Cut off the severely affected branches to avoid more infestation. Dip your pruning shears in rubbing alcohol before trimming the branches.

2. Crepe Myrtle Bark Scales (CMBS)

As the name already says that these bugs only attack on crepe myrtles. Crepe myrtle bark scales are tiny white bugs. It is a very serious pest of crepe myrtle. Because it spread at an alarming rate.

It causes small white spots on the bark of crepe myrtles. It also reduces the blooms drastically. Even there might be no flowering at all. If untreated these scales spread very rapidly and produce clusters of white spots.

Control Measure

Once you detect these bark scales you have to apply insecticides every year in April-May month. Treat your crepe myrtles with the best insecticides (our pick: Bonide (BND611) – Annual Tree and Shrub Insect Control)

If you have just spotted them in the early stage, scrub the barks with dish soap and a soft brush to get rid of them. In case of heavy infestation cut off those branches. Burn the debris or wrap them in a bag and throw them in the garbage. Otherwise, it will spread to other plants.

Apply dormant oil and neem oil(our pick: Garden Safe Neem Oil Extract Concentrate) on your crepe myrtle barks. They are very safe and effective against bark scales. The recipes are given below.

#Recipe 1:- Dormant Oil Recipe

Ingredients:

  •  1 tablespoon of liquid soap
  •  250 ml of oil like soybean oil or vegetable oil. 

Steps:

  • Mix the oil and soap together and store it in a bottle.
  • Then mix 4 tablespoons of this mixture with every liter of water 
  • Pour it into the sprayer and spray twice a week.
  • But avoid using it on the flower buds.

#Recipe 2:-Neem Oil Recipe

Ingredients:

  • 2 tablespoons of neem oil
  • 5 liters of water

Steps:

  • Mix neem oil and water 
  • Spray on a regular basis except for the flowering season.

3. Wood Rot of Crepe Myrtles

Sometimes when heavy pruning is practiced on crepe myrtles the barks get wounds. Then these barks easily get damaged by frost or sunburn. These wounds become susceptible to various diseases.

A white fungus called “Turkey Tail” attacks these decayed woods very fast. It causes white spongy layers on the woods and causes wood rot. It’s sometimes called white rot also. This is a very serious problem of crepe myrtles. Because as the wood rots, the branches will start falling off.

Control Measure

Avoid trimming the crepe myrtles too heavily. Do not keep the barks wet while watering. Keep the wounded areas dry as much as possible.

Always water the crepe myrtles at the base in the morning. Remove the rotted branches with a sharp shear before they fall off and cause any accident.

Conclusion

In this writing, I have tried to explain all the reasons why there are white spots on crepe myrtles. I hope this information helped you fix the white spot problems on your lovely crepe myrtles. 

Get them plenty of sun and good airflow to prevent fungal problems. Apply insecticides and fungicides at the right time. The spots will be gone soon.

Share your experience with us and let us know if you have any further questions in the comments below. 

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