Hoya plants are no longer strange plants for indoor or office plant lovers. This plant takes on its beauty from its large inflorescences, verdant foliage, and sweet fragrance. Hoya plants also often face a number of health problems such as fungal diseases, insect attacks, or infections caused by waterlogging.
Hoya fungal leaf spot is one of the common problems that you need to learn about and take effective preventive measures. Leaf spot disease is caused by a fungus that forms and attacks the leaves of plants. Brown spots and black spots will appear and spread to the entire foliage in a short time. Why do black spots appear on the leaves of hoya plants? How to treat leaf spot disease? How to prevent leaf spot disease? To answer these questions, let’s explore the details in this article.
Bacterial Leaf Spot Hoya: Signs And Symptoms
To find effective treatment and prevention of leaf spot diseases, you need to identify the early signs and symptoms of this disease. Leaf spot disease is very common in hoya plants and spreads quickly to all other leaves. Leaf spot disease will manifest as small black or brown spots appearing. They are usually round and small in size, then develop into large circles or brown or black patches.
In addition, dark spots can also have different shapes, varying in size from a few millimeters to several centimeters. They can appear on the surface of the leaf or inside the leaf. Black spots may appear singly or form large patches on the surface of the leaves, stems, or flowers of hoya plants.
Brown, yellow and black spots can appear on all parts of the plant such as leaves, stems, and flowers of hoya plants. Leaf spot is a combination of many different fungi that cause this condition. Therefore, it will be difficult for you to determine the exact cause or type of fungus that causes leaf spots in hoya plants.
What Is The Cause Of The Leaf Spot In Hoya Plants?
Leaf spot disease is caused by a fungus that thrives in warm weather and humid environments. The airborne fungal spores will move continuously and attach to the leaves of the plant. They will grow and enter the cells of plants through stomata or open wounds. In particular, this process will take place more quickly when plants show signs of weakened health. Here are some basic causes of hoya plants getting leaf spot disease.
Water Remains On The Surface Of The Leaves
Humid environments are favorable conditions for fungi to grow and attack plants. If you have a habit of watering the leaves of plants, the fungus will easily grow and attack the leaves of plants as they mature. The surface of the leaves is always wet, which will provide an ideal environment for the fungal spores in the air to have a chance to multiply. In particular, if you wet the leaves of plants at night, it will take a long time for the leaves to dry. So the fungus will have more time to grow and penetrate the cells in the leaf.
Continuous Misting
Hoya plants are native to tropical and subtropical regions. Therefore, they are very fond of environments with high humidity. However, constant misting to maintain plant moisture will also increase leaf spot disease. Tiny water droplets will stick to the surface of the leaves and create a humid environment. This is the ideal environment for fungal spores to attach to the leaves and mature quickly. They will also spread at a rapid rate when the humid environment is maintained for a long time.
High Humidity
High humidity is also the cause of increased leaf spot disease in hoya plants. It will also cause wetting of the leaves, flowers, and stems of plants. A constantly humid environment plus poor air circulation will be ideal conditions for fungi to grow. The fungal spores will quickly attach to the surface of the leaves and penetrate the cells for destruction. As a result, the cells will die and become deformed, the chlorophyll in the leaves will be lost, and black and brown spots will begin to appear.
Area With A Lack Of Air Circulation
Poor air circulation is also the leading cause of leaf spot disease in hoya plants. Uncirculated air creates a favorable environment for fungi to grow. If you put the potted plant in an area with sunlight and air circulation, the fungus will not be able to grow due to the effects of the outside environment. Wind and sunlight will reduce the density of airborne fungal spores and limit their density in an area.
Infected Pruning Tools
As you know, the fungus is one of the bacteria that is difficult to destroy even if you use medicine. Fungal spores will hide everywhere and move continuously from one location to another. If you use an infected pair of scissors or pruners to prune another plant, the leaf spot will spread quickly. This is because the fungus has attached to the pruning tool and quickly invades new leaves from the open wound to attack the cells.
In addition, the pots are placed too close to each other so that they have no space for air circulation and separation will also be favorable conditions for fungi to spread from one plant to another. If you detect early signs of leaf spot disease, isolate the plant from other plants to prevent it from spreading to all of your indoor plants.
Methods Of Treatment Of Leaf Spot Disease
Leaf spot is a difficult disease to treat definitively and brown spots can spread rapidly to otherwise healthy leaves. So, if you spot the early signs, you need to take some of the remedies below.
Isolating Plants With Leaf Spot Disease
The first and most important thing you need to do is isolate the plant with leaf spot disease. The goal is to avoid spreading the disease to other plants in the same space. Let’s move the healthy plants to another area. However, you need to make sure that the light and environment are not changed too suddenly to avoid undue stress on the plants.
Remove Stems And Leaves Infected With Leaf Spot Disease
Most fungal leaf spot diseases hurt plant health. They cause leaves to turn yellow, brown, and black and gradually fall off in mass. If you notice any signs of a leaf spot, prune diseased leaves immediately.
You need to use clean disinfected scissors or pruners to avoid introducing new plant pathogens. Infected stems and leaves should be handled with care and avoided near other plants. Next, you need to clean the open wound to prevent insects and bacteria from entering the plant’s cells. After you have finished pruning the diseased leaves, disinfect the pruners again to prevent the spread of leaf spot disease.
Using Neem Oil To Treat Leaf Spot Disease
You can use neem oil to treat fungal leaf spot disease in hoya plants. Neem oil is known as a natural insecticide and is safe for humans and pets. Here are some steps you need to pay attention to when using neem oil to treat leaf spots.
- Use a cotton swab or soft cloth soaked in neem oil and apply it to the entire leaf of the plant.
- Make sure the neem oil covers the entire leaf surface, both the top, and bottom.
- Usually, fungal patches or black spots will also appear on the underside of the leaves.
- Let the neem oil soak into the leaves for a few hours before you wash it off.
- Do this process every few days until the fungus is gone.
- Leaf spot disease will not be completely cured after a few uses of neem oil. You need to do it regularly and prevent hoya plants.
- Leaves with lots of brown and black spots will not be able to turn green again.
- Small yellow spots or mild damage to the leaves may cause them to turn green again.
- Alternatively, you can use natural insecticides like a cinnamon essential oil. Cinnamon essential oil is also effective in eliminating insects, harmful bacteria, and fungi in hoya plants.
Use Fungicides
Fungicides are the most effective method for treating fungal leaf spot diseases. Fungicides will help you control disease quickly and kill fungi in your plants in a short time. You should use a fungicide that contains copper or sulfur. These fungicides have been shown to be highly effective against leaf spot diseases. You just need to use the dosage and frequency as recommended by the manufacturer and the important information printed on the package.
Fungicides are the fastest and most effective, but should only be used as a last resort. Any chemical pesticide will affect plants depending on the extent. They will have adverse effects on plants and affect the health of humans and animals as well as negatively impact the natural environment.
Measures To Prevent Leaf Spot Disease
Prevention is the best way to ensure and maintain stable plant health. Once plants are infected, they will need time to treat and recover. One thing is for sure, they will be affected by the growth rate and beauty of the plants. Therefore, you need to learn and develop reasonable preventive measures to avoid fungal diseases.
Proper Watering
Proper watering is the most important precaution you need to take. Over-watering causes waterlogging and leads to root rot which is also the cause of leaf spot disease. Fungi and bacteria are very fond of moist environments and the droplets on leaves and stems are factors that promote the growth of fungal spores.
You should not water the leaves, especially at night or on wet days. The surface of the leaves is always wet, creating favorable conditions for fungi to penetrate inside the cells and attack them directly. Always water when there is sunshine and good air circulation.
Reduce Humidity And Maintain It At An Ideal Level
A humid environment is a leading factor for fungi to multiply and thrive. So you need to find a way to reduce the humidity in the air. You can use a local humidifier to maintain the ideal humidity for your hoya plants. A local humidifier will not change the humidity in the entire house, but only the area where you place it. In addition, you can also use a small fan to increase air circulation in the room. Take advantage of the sun or artificial light to enhance the ability to evaporate and dry the air quickly.
Prevention Of Some Other Fungal Diseases In Hoya Plants
Hoya plants can also be easily infected with a number of different fungal diseases. You need to learn the details of these fungi for early detection and treatment.
Botrytis fungal infection: This fungus usually attacks the inner leaves of plants. Like most fungi, they also grow quickly when the environment is moist. Fungal spores that are gray or light brown enter the leaves through open wounds or stomata to destroy the cells. Hoya plants will quickly die if you do not detect and treat this fungus in time.
Powdery mildew: This is the most common disease that almost any plant species is susceptible to. The telltale sign is white or light gray chalk appearing on the leaves. A white coating can also be a sign of this disease. Use a soft cloth to wipe clean and neem oil to clean both sides of the leaves.
Sooty mold: Pests are also responsible for this common plant disease. Aphids, scales, or whiteflies will often leave sap from the leaves they have eaten. From there, the sooty mold will form and attack the leaves of the plant. To kill this disease, you need to use a combination of methods such as fungicides, isolation, and double-sided cleaning of the iron with neem oil.
Final Thoughts
Hoya plants can easily get some fungal diseases if the environment is always wet. Some of the reasons for the rapid growth of fungal spores are over-watering the leaves, too much misting, high humidity, or over-watering that causes waterlogging and root rot.
To treat fungal diseases, you need to isolate the infected plant from other healthy plants. You can then use neem oil, cinnamon essential oil, or a fungicide to kill the fungus depending on the severity of the plant. Don’t forget to take precautions like watering properly, maintaining ideal humidity, and placing the potted plant in an area with good light and air circulation. Clean both sides of the leaves regularly to remove white patches and detect early signs of leaf spots.