Have you ever noticed brown spots on your favorite Hoya leaves? These are caused by a fungal disease known as Hoya Fungal Leaf Spot, and it’s one of the most common diseases to affect this type of plant. This article will discuss the causes and best methods for treating this problem. We’ll also offer tips on how to prevent it from occurring in the future. Read on to learn more about this pesky disease and how to get rid of it!

What Does Fungal Leaf Spot Look Like

Fungal leaf spot is one of the most common problems that affect hoya plants. The spots are small, round, and usually dark brown or black in color. They can appear on the leaves, stems, and flowers of the plant. Leaf spot is caused by a variety of different fungi, and it can be difficult to identify the exact cause of the problem. Treatment for fungal leaf spot usually involves using a fungicide to kill the fungus, and pruning of the diseased leaves to prevent it from spreading.

Signs and Symptoms

Hoya plants are susceptible to a range of fungal leaf spot diseases. The most common symptom of a fungal leaf spot disease is the appearance of small, dark spots on the leaves. The spots may be circular or irregular in shape and can vary in size from a few millimeters to several centimeters. The spots may be raised or sunken, and they may have yellow, brown, or black centers. Leaf spots may occur singly or in groups, and they may coalesce to form large, unsightly blotches. In severe cases, the entire leaf may turn yellow or brown and wither. Older leaves are usually more heavily affected than younger ones.

Fungal leaf spot diseases are often favored by warm, humid weather. Splash watering can also promote these diseases by splashing water-borne spores onto the leaves. Once spores land on a leaf surface, they germinate and penetrate the leaf tissue through natural openings or wounds. The fungus then begins to grow within the leaf, causing the characteristic spotting symptoms.

What Causes Fungal Leaf Spot

Fungal leaf spot is one of the most common problems that house plant enthusiasts face, and it can be caused by a number of different things.

1. Excess Water On Top Leaves

Splashing water on your Hoya plant either by watering from above or by misting your leaves directly is the top reason plants get fungal leaf spots. It’s important to keep the leaves dry, and try to keep the soil off of the leaves as well.

2. Over-Misting

One of the most important things to avoid is over-misting. Hoya plants are native to tropical and subtropical regions, so they’re used to high humidity. But too much moisture can lead to fungal leaf spot, and as mentioned before, if you mist your plant’s leaves directly, it can create the perfect environment for fungus to grow on your plant’s leaves.

3. High Humidity

Just as over-misting and excess water on the leaves can cause fungus spots, the humidity being too high can also make your Hoya plant more susceptible to fungus spots. Even though these plants naturally live in a tropical climate, too much humidity can be detrimental to their health.

4. Lack of Air Circulation

Lack of air circulation is one of the leading causes of Hoya fungal leaf spot. When the leaves of your plant are constantly wet, it creates the perfect environment for fungi to grow and spread.

5. Un-sanitized Tools

Just as a utensil used by someone with a stomach bug can transfer that bug to you, using pruning tools or other plant tools that were exposed to any fungi can easily spread that fungi to another plant if the tools are not sanitized. 

6. Transferred From Other Plants

One of the most common ways that hoya plants become infected with fungal leaf spot is when they are transferred from other plants. This can happen either through direct contact with an infected plant, or by coming into indirect contact with contaminated soil or water.

Leaf Spot Treatment

To treat leaf spot, there are a few crucial steps to take. You’ll want to begin treatment as soon as you see any leaf spots appear, to give your plant the best chance at recovering. The basic steps are:

  1. Quarantining the diseased plant
  2. Removing affected leaves and stems
  3. Treating the plant with neem oil
  4. Treating the plant with home remedies
  5. Use fungicide to kill the fungus causing the spots

Let’s go a little deeper into this treatment plan to ensure your plant gets the best care you can give it.

Quarantining Diseased Plants

If you have a hoya plant that is diseased, it’s important to take action to prevent the spread of the disease. One way to do this is to quarantine the diseased plant. Move the plant away from healthy plants, either to the other side of the room or in an entirely different room.

 This is one of the most important steps to prevent the fungus from spreading to your other plants, so don’t skip this step! Just ensure that your plant still gets the required amount of light so it doesn’t rebel and go into shock.

Removing Affected Leaves And Stems

While not all fungal leaf spot diseases are harmful to plants, they can cause the leaves to yellow and eventually drop off. If you notice any of these symptoms on your Hoya plant, it is important to take action immediately in order to prevent the spread of the disease.

Much like quarantining your plant, removing affected leaves and stems is crucial to preventing the spread of the disease. Use sterilized pruning shears to cut off any diseased part of the plant. Be sure to dispose of the affected leaves and stems in a garbage bag so that they cannot spread the disease to other plants. Make sure to re-sanitize your pruning shears right after this step, to keep your other plants safe the next time you use the shears.

Treating With Neem Oil

Neem oil is a natural, effective way to treat Hoya fungal leaf spot. Simply apply the oil to affected leaves with a cotton swab or soft cloth. Be sure to cover the entire leaf, including the underside where the fungus is likely to be present. Allow the oil to penetrate for several hours before rinsing with clean water. Repeat this treatment every few days until the fungus is gone.

Keep in mind, treatment of the fungus will not make the leaves turn green again. Once a part of the leaf has turned brown, it will not become green again. Yellow spots may revert back to green depending on the severity of the diseased spot, though!

Using Home Remedies

Believe it or not, there are effective ways to rid your plant of fungus without any damaging effects or harsh fungicides. Cinnamon is a very commonly used spice that has natural anti-fungal properties, making it the top choice to treat fungus infections in plants for people who want a more natural remedy.

Using Fungicides

Fungicides are one of the most important tools in the fight against Hoya fungal leaf spot. They help to control the spread of the disease and can eventually eradicate it from your plant.

The best fungicide to use is one that has copper or sulfur in it. These fungicides are proven to work well against fungal leaf spot on hoya plants, and they do so quickly with the least amount of adverse effects for your plant.

An additional note on fungicides: even though they are the fastest way to kill fungus on your plant, use them as a last resort. Some fungicides can be effective at preventing or treating fungal leaf spot, but they should only be used as a last resort. Be sure to follow the directions carefully and always read the label before using any pesticide 


Fungal leaf spot is one of the most common problems that hoya plants face. The good news is, there are a few things that you can do in order to prevent this problem from occurring in the first place. Prevention is always better than trying to nurse your plant back to health, so make sure to take any preventative measure you can.

Avoid Watering Top Leaves

Watering the top leaves of your hoya plant can cause leaf spot to occur. The water droplets can act as a magnifying glass and intensify the sun’s rays, burning the leaves. It is best to water your hoya plant at the base, keeping the leaves dry.

Reduce Humidity Levels

Make sure your Hoya plant is not in an environment that is too humid. This is one plant that enjoys some humidity, but too much can cause serious problems like fungal leaf spots. Using a small fan close to your plant is an excellent way to help prevent fungal leaf spot. Additionally, using a humidity meter to monitor humidity levels will help even more.

Mist And Water Early In The Day

Mist and water early in the day is one of the best times to water your hoya plant. The morning mist will help to keep the leaves hydrated and the water will evaporate quickly, minimizing the chance of fungal growth.

Additional steps you can take to prevent disease in your Hoya plant are:

  • When possible, start with healthy plants. If you’re starting with plants that are already stressed or have other health problems, they will be more susceptible to fungal leaf spot.
  • Make sure that your hoya plant has plenty of air circulation. This means keeping it away from other plants, as well as not placing it in an area where there is not enough airflow. If possible, try to position your hoya plant near an open window or door.
  • Water your hoya plant only when the soil is dry to the touch. Overwatering is one of the main causes of fungal leaf spot, so it’s important to be careful not to do this.

Brown spots are caused by a fungal disease known as Hoya Fungal Leaf Spot, and it's a common diseases to affect this type of plant.

Other Fungus Issues on Hoya

Hoya plants are susceptible to a number of different fungal diseases. Here’s a short list of fungal diseases that may affect your Hoya, with a small snippet of information about each.

Botrytis Fungal Infection: This infection is most likely to attack the inner leaves of your plant, as like many other fungus problems, it thrives on humidity. This infection is characterized by gray or light brown spores on the leaves, and it can kill your plant very quickly if the plant isn’t treated.

Powdery Mildew: This fungal infection is one of the most common in houseplants, and it’s fairly easy to identify. If you see a white or light gray powdery substance on the leaves of your plant it is more than likely powdery mildew. This problem is fairly easy to rid your plant of, and as long as the fungus hasn’t taken over a majority of the plant, it should fully recover from this problem.

Sooty Mold: Sooty mold is a rather scary name for a fungus, but this is typically caused by another problem that you should be aware of: pests. Aphids, scale, or whitefly will often leave behind sap from the leaves they are feeding on, and that then causes sooty mold to form on the leaves. This is one of those issues that requires a multi-directional treatment that includes a fungicide and pest control.

FAQ Hoya Fungal Leaf Spot 

Does Fungal leaf spot harm humans?

Fungal leaf spot does not harm humans, but it can cause the leaves of hoya plants to become discolored and fall off. The fungus can also spread to other plants in the home, so it is important to treat it as soon as possible. Regardless, it’s a good idea to use personal protective equipment such as masks and gloves when treating and removing infected leaves from your plant, as well as when you are handling fungicides.

More Houseplant Resources

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