Philodendron Has Brown, Yellow or Black Spots?

A philodendron is a very popular type of indoor plant that is known for their hardiness and ease of care. That doesn’t mean that they are impervious to plant diseases, just like any indoor plant. Luckily, there are lots of ways to identify and care for an unwell philodendron.

The most common cause of brown, yellow, or black spots on a philodendron is leaf spot disease. This is caused by bacteria and fungus that are introduced to your plant from the outside world. Damp conditions are ideal for the fungus to grow. You can treat leaf spot disease if you catch it early.

Though leaf spot disease is treatable, it is important to be able to recognize the signs and catch it early. In this article, we will go over the signs of leaf spot disease, treating the disease, and prevention of the disease. We will also discuss the other possible causes of the spots on your philodendron.

Spotting Leaf Spot Disease

Leaf spot disease is quite easy to spot- if you know what to look for. There are a variety of philodendrons, and each of these varieties has a subtle variation on the leaf pattern and color of the plant. It is possible to confuse the natural coloring of the plant with a disease, so be sure to get to know your plant’s natural patterns before fixing a problem that isn’t there.

Once you’re sure the spots on your plant are not natural, you can then see if the marks match those of leaf spot disease, also known as bacterial leaf spot. The spots are usually seen as brown spots, with yellow halos directly around the spots. They can also manifest as dark spots with black edges.

These spots can occur anywhere on the leaf, like the top or bottom, or along the edges. As the lesions grow larger, the leaf will get thinner and more delicate or brittle. The leaves will easily break off if you touch them.

These spots are irregular in shape. There is no uniform pattern, and they may spread along the leaves seemingly randomly. As leaves are infected, other leaves around them may become infected, too. The same goes for nearby plants.

Treating Leaf Spot Disease

First, if you notice leaf spot disease on your philodendron, move it away from any other plants in your house. Leaf spot disease is highly contagious and can jump quickly from your infected plant to your healthy one.

Next, stop spritzing your philodendron immediately. Surface water on the leaves is one of the main ways that the bacteria that causes leaf spot disease comes in contact with your plant. Also, the moisture from misting your leaves will only help the bacteria grow.

Trim all leaves that are infected, and dispose of them properly. Do not add them to your garden compost, as the disease will continue to grow and may then attack your outdoor plants, becoming even harder to get rid of.

You can treat your philodendron with a fungicide, like Bonide Copper Fungicide. Apply the fungicide to the top and bottoms of the leaves and along the stems of the infected leaves. While this fungicide won’t kill leaf spot disease, it will prevent the spread of the disease.

It is extremely important to apply this as soon as you find leaf spot disease on your philodendron, so it is good practice to check your plants weekly for signs of illness.

Preventing Leaf Spot Disease

As we have just learned, you cannot get rid of leaf spot disease once it has appeared. You can stop it from spreading, but it will still be there. That is why the best defense against leaf spot disease in your philodendron is prevention.

In this section, we will learn some important preventative measures to avoid these brown and yellow spots on your plant.

Avoid Overwatering

Like with any plant, overwatering is the number one cause of illness on your philodendron. This is because overwatered plants cannot use all of the moisture in their soil. The damp dirt then provides a perfect breeding ground for bacteria, just like the one that causes leaf spot disease.

Provide Proper Air Circulation

One of the best ways to prevent leaf spot disease is to make sure that the air around your plant and in its soil has proper air circulation. 

To provide proper air circulation when watering your plant, use a chopstick to carefully prod the dirt around the roots, and create pockets of air throughout the plant. This will allow your philodendron’s roots to get the air needed to grow and help prevent the roots from getting bogged down by excess water and rotting.

It will also allow the water to spread more evenly through the plant’s roots when you do water it.

To provide proper air circulation around your plant, make sure your plant is in an open room in the house that gets airflow. While you don’t want to point a fan directly at your plant, you can place a fan in the room with your plant to make sure there is air circulation.

The reason why this is so important for your plant is that airflow helps surface moisture to evaporate. People often say that misting your plants helps to raise the humidity around them, but in fact, this water often just sits on the plant’s leaves and provides a good catalyst for bacteria.

Having a fan in the room with your philodendron will help the leaves to dry off when you do mist them.

Avoid Overhead Watering

Since leaf spot disease is spread to your plant by the bacteria in water sitting on your plant’s leaves, it is important to limit the amount of moisture that sits on your plant’s leaves. This means that instead of sprinkling water overhead of your plant, you should water your plant with the watering can as close to the soil as possible.

This will help limit the amount of water on your plant’s leaves and will limit the bacteria delivered to them. 

This Nerseki Long Spout Watering Can is the perfect tool to use to deliver water as close to your philodendron’s roots as possible.

Don’t Buy Infected Plants

Even if you do all of the preventative measures above, it won’t do anything if the plant you’re treating is already infected. One of the best ways to prevent infection in your house plants is to examine all plants before buying them. Don’t bring any plants into your home that have signs of disease, especially a highly contagious one like leaf spot.

Other Possible Causes for Spots on Your Philodendron

Though leaf spot disease is the most likely culprit of the marks on your philodendron, it is not the only possible cause of distress in your plant.

There are many other possible causes, which range in reason from temperature to improper provision of nutrients. They are:

  • Bacterial blight caused by bacteria delivered in water. 
  • Cold injury caused by temperatures below 50°F (10°C).
  • Magnesium deficiency caused by insufficient magnesium.
  • Tip curl caused by over-fertilization.

Final Thoughts

While there are multiple reasons your philodendron might have spots on its leaves, the most likely one is leaf spot disease. This is a disease that is controllable but not curable. 

It is important to check your plants’ health weekly to ensure you catch any diseases early and provide your plant with the proper light, air circulation, and watering processes to keep it healthy.

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