Fungus On Areca Palms – How To Treat? (Black, White, and Brown Spots)

Breezy houseplants like the Areca Palm help make every day at home feel like you’re on vacation. Despite its popularity, this Madagascar native is a threatened species in the wild and was once considered endangered.

Nowadays, you can find Areca Palm in the gardens and streetscapes of places like Jamaica, Cuba, and Florida. It serves as an air purifier and decor piece in colder climates to brighten indoor spaces. 

Although Palms appear strong and hearty, they are susceptible to disease and pests. Spots on Areca Palm have different causes; brown spots are leaf spot fungi, black spots can be bud rot or Graphiola leaf spot, while white spots are a mealybug infestation. The best treatment for fungus on an Areca Palm is a copper fungicide, as it’s a natural product and is effective against fungus and bacteria.

We’ll look at each affliction in detail so you can diagnose your plant correctly. 

Types of Areca Palm Fungus

Palms have a long history of battling disease and pests. This plant is native to warm, humid climates; unfortunately, diseases and bugs thrive in these conditions. Often these diseases come from the soil or are blown through the wind from palm tree to palm tree. 

You may think your Palm is safe at home, but these diseases travel in plant nurseries too. Any spots on your Palm leaves, whether brown, black, or white, are cause for concern. 

What Causes Brown Spots on an Areca Palm?

If you notice brown patches on your Areca Palm leaves, this is a sign of a disease called leaf spot, which is caused by fungi. Several different fungi can cause leaf spots, examples being annellophora, exserohilum, pestalotiopsis, and stigmina.

Although their names vary, all these fungi act similarly. Their spores are spread through the wind or rain. If you’ve bought your Areca Palm from a nursery, the spores were likely spread through human activity or pests. 

These brown spots are usually wet and soft to the touch. Sometimes these brown patches will turn black. Often you will also see a ring of yellow or orange discoloration around the spot. Leaf spot typically affects young Palms. 

So how do you stop these spores from killing your entire Areca Palm plant? The first step is to prune any diseased leaves. Avoid wetting your Areca Palm from above, as this can cause the spores to lift and travel to other leaves or neighboring plants. You can use a fungicide if the issue persists in preventing the further spread of fungi spores. 

What Causes Black Spots on an Areca Palm?

Black spots on your Areca Palm are often caused by two issues: Graphiola leaf spot or bud rot. 

Graphiola leaf spot, also known as false smut, only affects Palms in the Araceae family like Areca Palms. Graphiola leaf spot looks like pinprick-sized black dots on the leaf. Fungicides cannot save the leaves once infected, but they can prevent the fungus from spreading to other leaves. The best remedy is to remove affected leaves immediately. Graphiola leaf spot attacks the lowest and oldest leaves on the Areca Palm.

Bud rot is caused by fungal and bacterial pathogens like phytophthora and thielaviopsis. Bud rot tends to affect Palms after periods of excessive rain or when temperatures drop too cold. Pathogens attack the leaves and form large black spots, which then cause the leaves to wilt. Like Graphiola leaf spot, this disease commonly attacks younger leaves first, then moves on to older leaves.

If bud rot is left unchecked, the leaves will eventually all die off. To prevent bud rot from worsening, avoid watering your Areca Palm from above and only stick to watering the soil. Copper fungicides are the most effective way to kill bud rot pathogens. 

What is the White Stuff on My Areca Palm?

Palm leaf with fungi
White spots and patches on Areca Palm leaves may look like powdery mildew or fungus. But really, these white spots are often a mealybug infestation. Mealybugs cluster up when they attack plants, giving off a fuzzy white appearance. They prefer to cluster where the leaf meets the stem, then spread to the outer edges of each leaf. 

Mealybugs are attracted to the sap in Palm leaves and will suck it out until the leaf dies. Although mealybugs can multiply rapidly, they are fairly straightforward to deal with. You can kill mealybugs by wiping your Palm leaves with an alcohol-soaked cloth. You can also use a neem oil spray or other insecticides.

How To Treat Fungus on Palm Trees

If you’re struggling to keep your infected Areca Palm alive, a fungicide is the quickest and most effective solution to remove the fungus. You can buy fungicide powders and sprays at any gardening center. They cater to various plants, although you can sometimes find formulas explicitly designed for Palms. 

Copper fungicide spray is one of the most effective fungicide treatments for Palms. It’s a favorite of gardeners and plant lovers because copper is a natural product and can be used safely in the home. Copper spray is also the only fungicide that is effective against both fungi and bacteria

How Do I Keep My Areca Palms Healthy?

Palm lovers should suspect any Palm they take home from the nursery may carry a fungal or bacterial infection. As long as you treat the infection in time, your plant can go on to live a healthy life. Since Palms are prone to disease, the trick to avoiding any subsequent infections is to keep your plant as healthy as possible. 

Palms like their soil moist but are susceptible to root rot, so avoid overwatering your Areca Palm. Since Palms are native to hot sunny environments, you need to keep your indoor Areca Palm in your home’s brightest, sunny location. 

If you live in an environment where the weather is hot enough to keep Areca Palms outdoors, be wary of cold overnight temperatures. Sudden cold weather can weaken your Palm and make it susceptible to disease. If you notice the temperature is dropping, consider bringing your Palm indoors or wrapping your Palm in a blanket. 

How Often Should You Water an Areca Palm? 

Areca Palms are fussy about their water intake and the type of water they receive. Since they are susceptible to root rot, it’s best to let the top 1-2 inches (3-5 cm) of soil dry out before you water your Areca Palm. Don’t leave the soil dry for too long, or else the leaves will crisp up and turn brown. 

Water your Areca Palm slowly so the water has a chance to be absorbed by the roots. Palms generally dislike fluoridated water. If your tap water is treated with fluoride, use rainwater or distilled water instead. 

Is Epsom Salt Good For Palm Trees?

Epsom salt
A popular DIY fertilizer making the rounds in gardening forums is Epsom salt. Epsom salt is a compound of magnesium and sulfate. It is a naturally occurring mineral, first discovered near the town of Epsom, London, close to 400 years ago. 

While you can’t eat Epsom salt, you can add it to water to create a mineral bath to soak in. Since Epsom salt is rich in magnesium, it can be used to supplement a magnesium deficiency in your Areca Palm. Magnesium deficiencies are usually characterized by bands of yellow on the tips of Palm leaves

Indoor Palm Plant Diseases

One of the most common diseases affecting Palm plants is Fusarium wilt. This fungal disease spreads through the soil and attacks the Palm’s roots. This inhibits the Palm’s ability to take in water, which can be fatal.

There are two strands of Fusarium wilt. Fusarium oxysporum f. sp. Canariensis only affects Canary Palms. But Fusarium oxysporum f. sp. Palmarum can affect common indoor Palm plants such as Areca Palms. Fusarium wilt causes leaves to turn brown and often attacks the lowest, oldest leaves first. 

The reason why this disease is so deadly is that there’s no cure. Typically Fusarium wilt bacteria are spread through infected gardening equipment, so always sterilize your tools before introducing any new plants to your home. 

Summary 

If you’re a Palm lover, keep in mind that this family of plants can be prone to disease. Many of these diseases are inflicted by environmental stressors such as rain or cold. But common houseplant species like Areca Palm can also be exposed to diseases at the nursery. 

Spots on Areca Palm have different causes; brown spots are usually leaf spot fungi, black spots can be a sign of a disease called bud rot or Graphiola leaf spot, while white spots are not a fungus but a mealybug infestation.

The best way to treat fungus on an Areca Palm is to use a copper fungicide. It is an effective treatment for both fungus and bacteria. It is loved by many gardeners because it’s a natural product that is safe for use in the home and will help your Areca Palm ward off any pests.