How to Get Rid of Rust Fungus on Monstera

Among the sprawling foliage and majestic split leaves of the monstera plant lies a potential adversary: rust fungus. While the monstera, with its tropical origins and Instagram-worthy aesthetics, this plant has cemented its place in many homes, it’s not impervious to threats. Brown, rust-colored blemishes can tarnish its vibrant leaves, and in more severe cases, lead to curling and shedding. But fear not, dear plant lover! While rust fungus may seem like a formidable foe, it’s a challenge that can be tackled head-on. Dive into this comprehensive guide to equip yourself with knowledge on its causes, identification techniques, treatments, and prevention methods to ensure your monstera remains the crown jewel of your indoor garden.

What is Rust Fungus?

In simple terms, rust is more than just the brownish spots you might see affecting your monstera. It belongs to a complex group of diseases resulting from the pathogenic fungi known as the order Pucciniales. Previously referred to as Uredinales, this group is diverse, boasting about 168 genera and around 7,000 species. To give you a sense of its vastness, over half of these kinds are from the Puccinia group.

What makes rust especially interesting and challenging are their unique features:

  • Obligate Parasites: These fungi aren’t your typical freeloaders; they absolutely need living hosts to grow and eat.
  • Complex Life Cycles: Rust fungi are noteworthy for having multiple spore stages throughout their lifespans, adding a layer of complexity to their biology.
  • Specific Host Preference: While you might think rust is a crazy attacker, they’re quite picky. Each rust kind likes only a few related plants. Knowing which rust is on your plant is super important for a good fix.

Armed with this knowledge, it becomes evident that combating rust fungus goes beyond surface treatment. It’s about really getting it and understanding how it really works. Source (

Rust Fungus On Monstera

Symptoms of Rust Fungi

Rust bugs exhibit a range of symptoms that, when spotted early, can be key for a quick fix. Here’s a rundown of the most common manifestations:

  • Vivid Spore Masses: One of the most recognizable signs of rust is the presence of colorful spore masses. These can range from shades of orange and yellow to brown and red, depending on the species of the rust bug. Such blobs typically appear as raised dots prominently displayed on the leaves or stems.
  • Rust on Blooms: While less common, some rust varieties can mess with the plant’s flowers, compromising their looks awesome.
  • Gall Formation: Certain types of rust will instigate the formation of galls, which subsequently become covered with the telltale spore masses.
  • Leaf Issues: Rust starts from the ground level and moves up, mainly hitting the underside of leaves. But the tops aren’t always safe. Over time, rust can cause a phenomenon known as witches broom growth, characterized by reddish, twisted stems and leaves. This is accompanied by cankers, oozes, and spotted needles. If you don’t act, rust can make leaves drop early. Really bad rust infections mess up the green parts of leaves the leaf’s green areas essential for photosynthesis, leading the plant into a state of starvation.

Spotting these signs is the first step to fighting rust bugs and getting your plant’s health back.

Fungal leaf spot monstera

How to Identify Rust Fungus on Monstera?

Given the variety and widespread nature of rust diseases, identifying their presence, especially on cool houseplants like the monstera, is super important. While rust might remind you of the old bicycle turning orange-brown in the shed, its appearance on plants, particularly the monstera, has distinct markers.

Distinct Characteristics of Rust Damage on Monstera:

  • Colorful Spots on Upper Leaves: Start by examining the upper leaves of your monstera. Yellow or white spots can signal the early stages of rust disease.
  • Pustules on the Underside: Turn the leaf over and look closely. You’ll likely see reddish to orange blister-like swellings. These are known as pustules, the breeding ground for spores.
  • Spots and Streaks: A defining feature of rust fungus on monstera is the appearance of orange or yellow spots, sometimes even streaks, predominantly on the underside of leaves. These aren’t just ordinary spots; they house the spores that facilitate the disease’s spread.
  • Leaf Deformation: As the rust fungus establishes its grip, it’s not uncommon for the monstera leaves to show signs of distortion. This could range from subtle warping to more prominent deformities.
  • Textured Spots: Upon closer examination, the orange-red spots on the monstera leaves may seem slightly raised or sunken. To touch, they might exhibit a powdery texture, a clear sign of rust fungus in action.
  • Expansion of Damage: If left unchecked, these small spots can coalesce, forming larger patches of rust-colored fungus. This, combined with a spread to the plant’s stems that turns them a distinct orange or red, indicates a severe infection.
Rust Fungus on Monstera underside of leaves

How to Control Rust Fungi

As cool as the bright green leaves of the monstera are, they can, sadly, get hit by that sneaky plant rust. But, with the right steps, you can totally fix this annoying problem. Here’s a full how-to on protecting your monstera from that pesky rust:

Swift Identification

Diagnosis is Key: Begin by ensuring that the symptoms you’ve observed align with rust fungus. While the rust-like spots are telling signs, other plant diseases can mimic these symptoms. Accurate diagnosis ensures you employ the right measures.

Immediate Actions

Isolation: If your monstera shows signs of rust fungi, promptly isolate it. This step minimizes the risk of the disease spreading from jumping to your other plants.

  • Pruning Affected Parts: While it might seem drastic, pruning and destroying leaves or plant parts showing rust signs can curb the disease’s spread. In extreme cases, if a plant is extensively infected, maybe just get rid of it, especially if you’ve got other monsteras or similar plants close by.
  • Lawn and Other Plants: Seen rust on your lawn or on plants like roses or pears? Here’s a quick tip: Regularly mowing the lawn and removing clippings can reduce the number of rust-affected leaves. Meanwhile, for plants like pear trees, removing nearby juniper bushes (potential hosts for the rust-causing fungus) can be beneficial.
My Monstera is healthy after control Rust Fungi

Treatment Options

  • Use of Fungicides: There’s a plethora of fungicides designed to tackle rust fungi. Opt for one suitable for houseplants, and always adhere to the instructions on the label. Remember, always ensure any product used is safe for indoor plants, especially if they’re easy to reach for pets or kiddos.
  • Consider the Environment: Rust fungi flourish in moist and stagnant conditions. To combat this, ensure your monstera enjoys good air circulation. Put it somewhere breezy to really slow down rust.
  • Watering Habits: Monstera overwatering can inadvertently create a conducive environment for rust fungi. Adopt a balanced watering routine, ensuring you only water your monstera when the top layer of the soil feels dry. This doesn’t just stop rust, it also keeps your plant looking great.

Preventative Measures

Pollinator Safety: If you’re treating outdoor plants, be ecologically responsible. Avoid using insecticides or fungicides when plants are flowering to protect bees and other pollinators. Always go for the green options that don’t hurt the planet or helpful bugs.

By embracing this multifaceted approach, you won’t just fix current rust problems on your monstera but also stop it from coming back. A little lookout and acting fast means your monstera stays a lively piece of your indoor space.

In conclusion, while rust fungi can challenge the health of your monstera, armed with the right knowledge and proactive measures, you can ensure its vitality. For more insights into plant care and troubleshooting, explore FamiPlants, your trusted guide in nurturing flourishing indoor green spaces.

Hi, I'm Cathleen Clemens. I graduated from Cornell University with a degree in plant science. I gained detailed knowledge about various kinds of plants and how to properly care for them. My experience has enabled me to easily detect any issues such as pest infestations, nutrient deficiencies, or signs of diseases in the plants.

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