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White Spots on Yucca – What Are They?

White Spots on Yucca – What Are They?

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Yucca plant belongs to the perennial shrubs of the Asparagaceae family and the subfamily Agavoideae.

It has around 40-50 species that are well known for their sword-shaped evergreen leaves and the stunning white flowers that grow on them.

Yuccas are commonly cultivated in gardens as flowering shrubs. Many species can produce eatable parts such as fruits, flowering stems, flowers, seeds, and, in rare cases, roots. 

When owning and developing a Yucca plant, a range of problems can emerge. White spots on its evergreen leaves are the most prevalent problem that this plant suffers from. 


White Spots on Yucca

Soft and armored scale insects are the most dangerous scales, and they might be the reason you see white spots on your Yucca. Mealybugs and Spider mites also attack the Yucca plant and can be detected when you observe white spots. Powdery mildew might also be the reason for these white spots.


Scale Insects Causing White Spots

Scale insects are popular pests that attack shade trees and shrubs. Scale insects can flourish on the leaves of your Yucca plant in large numbers if they take an affinity to it. 

They might not even move much or appear to be normal spots, but they are bugs that you would not want to have around as they will feast on the leaves of your Yucca indefinitely. 

Examining the leaves and seeing if the spots are white is an easy way to judge whether these are white-scale insects.

Scale insects attacking your Yucca plant have two types:


Armored Scale Insects

Armored scales are very tiny, typically measuring about one-eighth of an inch long. 

They have an oval shape that is mildly enlarged. Their typical name is derived from the waxy, defensive scale covering that protects their bodies while feeding.

Armored scales frequently mix in with the bark of the Yucca plant, so they may go unnoticed until harm is obvious.

It is very important that you treat the armored scales when they are in the early stage, as after that, there is no solution other than throwing the plant away.


Soft Scale Insects

Soft scales are smoother than armored scales and have a convex structure instead of the bumps found in armored scales. 

They are also bigger than armored scales, measuring about one-fourth of an inch long.

Soft scales, unlike armored scales, nourish on phloem tissue spotted in the Yucca plant rather than specific plant tissue. 

Soft scales are mostly discovered on the lower part of leaves and stems, although a few species may be detected on the top surface of the leaf.

If the infestation of soft scales is heavy, you will notice yellow leaves, and often white spots also appear. 

Soft scales can be bothersome long before any noticeable symptoms appear. Treating soft scales is also very crucial and if they are allowed to thrive, white spots keep growing, and ultimately the plant dies.


Pest Infestation

Two of the very common pests that attack house plants are mealybugs and spider mites. Like any other shrub, Yucca is also prone to these tiny pests.



Mealybugs can leave a dense, waxy residue on your plants. This wax will typically build up on the plant’s leaves, and you’ll also observe it on the ends of the branch.

These pests are typically pink or grey in color, with a silky exterior in regions where they feast. 

If the mealybug infection keeps growing, you may observe white spots on various parts of the Yucca, and the plant may start to die.

These bugs produce honeydew which attracts other bugs, and a colony of problem-causing pests is formed all over the leaves and branches of Yucca. 

Examine for small white spots of cottony wax on Yucca to help you determine them.

Remember that some mealybugs will not harm your plant. However, once they start to develop and feed intensely, your Yucca will perish quickly.


Spider Mites

Spider mites are small spiders that measure about 1/50 inch in length. They are oval in shape and yellow or greenish in color. It is hard to detect them since they are very tiny in size.

If you detect tiny white spots on the Yucca plant, there are chances that it is the spider mite. 

Place a piece of paper underneath the Yucca and shake the leaves thoroughly, you will notice tiny specks moving.

Spider mites can be easily spread through your hands, clothes, and even watering cans. When spider mites attack your plant, they struggle to thrive, so it is important to treat them right away.


Powdery Mildew

Finally, if you observe a powdery white material on your Yucca plant, it is likely that you have mildew rather than bugs entering the plant. 

This appears as white spots initially, and if not handled properly ahead of time, it can flourish and take over the leaves.

Temperature fluctuations and a very moist climate can provoke mildew accumulation on your Yucca plant, so remember this when cultivating the plant. This is one of the simplest diseases to recognize because the symptoms are distinct and occur immediately.

As soon as it is harmed, white spots will occur on the stems and leaves of the Yucca plant. 

The lower leaves are more impacted by the powdery mildew, but it won’t take long before the symptoms spread throughout the plant. That white powdery compound will cover any part of the plant which is above ground.


Treatments for the White Spots on your Yucca Plant


Removing Scale Insects

  • It is hard to remove the scales using a spray, so you must do it with your hands. You will need some cotton balls and rubbing alcohol.
  • Gently rub the part of the plant that has white spots with the cotton ball dipped in alcohol.
  • You must do it frequently until you are sure that the scales have gone forever.
  • This trick will work for both soft and armored scales.


Treating the Pests

  • Both mealybugs and spider mites can be treated using some neem oil. Unlike scale insects, these pests are less resistant.
  • You can use alcohol for treating the pests just as you do to remove the scale insects.
  • Remember to separate the afflicted Yucca so it won’t infect other plants nearby.


Eradicating Powdery Mildew

  • You can use neem oil or other horticulture oils to treat powdery mildew.
  • Secondly, improve the air circulation of the place where you’re planning to grow the Yucca.
  • Also, avoid overwatering your Yucca as it provides the environment for the development of mildew. Try planting the Yucca in pots with drainage holes.


Frequently Asked Questions about White Spots on Yucca


Does overwatering the Yucca plant lead to white spots?

Unfortunately, overwatering your Yucca will cause problems for the plant. It will lead to the development of powdery mildew, which is among the leading cause of white spots on the plant. Thus,  avoid this habit if you must.


Are white spots threatening to the Yucca plant?

If you notice white spots on any part of your Yucca, it is very important that you treat them right away. These white spots might be the pests that attack houseplants. If you leave this condition untreated, these pests will eat up your plant.