ZZ Plant Fungus

Zamioculcas zamiifolia, or ZZ plants, have become one of the world’s most popular houseplants because of their beauty and hardiness. These plants are very low maintenance to grow and are pretty tolerant of neglect when they are growing healthily.

If a ZZ plant is not growing in the right conditions, it is susceptible to fungal diseases. Fusarium, Pythium, Rhizoctonia, and Phytophthora are the main fungal families that infect ZZ plants. These can cause rhizome and stem rot or fungal leaf spot.

If you know how to identify the different fungal issues, you can treat them and save your plant before it is too late. In this article, we look at the various types of fungi that commonly affect ZZ plants and how to treat the fungal diseases they cause. We also discuss ways to prevent fungal diseases in ZZ plants.

Happy woman cleaning zz plant at home

What Types Of Fungi Affect ZZ Plants?

There are millions of types of fungi out there – most of them have yet to be described by science – and only a handful of them affect ZZ plants.

Some fungi have more detrimental impacts on plants than others, and the different types can look quite different.

The main types of fungi that harm ZZ plants are:

  • Fusarium
  • Pythium
  • Rhizoctonia
  • Phytophthora
  • Ascomycete
  • Capnodium

Fungal Diseases In ZZ Plants

Generally, ZZ plants are not particularly disease prone. When ZZ plants are growing in the right conditions, and they get the appropriate amount of water, they are not susceptible to fungal diseases.

However, overwatered ZZ plants that live in perpetually soggy soil can develop fungal diseases such as rhizome or stem rot and fungal leaf spot.

Read more: ZZ Plant Root Rot: Causes, Important Detection Tips & Solutions

Symptoms Of Rhizome & Stem Rot In ZZ Plants

If you catch your ZZ plant in the early stages of rhizome and stem rot, one can easily rescue it. The key is detecting it before it gets too bad.

Look for the following symptoms of early-stage rhizome or stem rot:

  • Soggy, waterlogged soil
  • Leaves turn yellow
  • New growth has leaves with brown tips
  • Drooping stems that look wrinkled

As the infection progresses, you will notice these symptoms:

  • Curling leaves
  • Signs of edema, like blisters on the leaves
  • Black spots on the stem near the base of the plant
  • The stem may look brown or mushy near the base
  • Wrinkled looking stems falling over completely
  • A stinky, rotten odor coming from the soil

How To Rescue A ZZ Plant With Rhizome Or Stem Rot

Stem or rhizome rot can be fatal, but if you catch it in time, you can take steps to rescue your suffering ZZ plant. Follow these steps:

  1. Take the ZZ plant out of its pot and have a look at the roots. You should see dark brown, mushy roots that do not smell healthy.
  2. Gently loosen the soil from the root system.
  3. Use a sharp, sterile pair of pruning shears to cut off the infected roots.
  4. Wash as much of the remaining soil off of the roots as possible. Put the root mass under a gently running tap.
  5. Repot your ZZ plant into a new pot (with adequate drainage holes) in new potting soil. Use a potting mixture that drains very well. A 50/50 combination of coco peat and perlite, mixed with a few scoops of compost, works very well for ZZ plants.
  6. Place your ZZ plant in a place that gets bright, indirect light, and keep it warm.
  7. Water your ZZ plant thoroughly, and then wait until the top half of the soil in the pot has dried before you water again. Finding the right watering cycle is key to keeping this plant happy.
  8. Do not worry if your ZZ plant does not show signs of new growth for several months. With care and a little patience, your ZZ plant will soon recover!

Fungal Leaf Spot In ZZ Plants

Fungus on a plant leaf

If you notice your ZZ plant developing black spots all over, it may have contracted fungal leaf spot. This is caused by airborne fungal spores that stick to water droplets on plants’ foliage.

Fungal spores can also stick to the feet of insects and be carried onto plants’ leaves. When aphids visit your ZZ plant, not only do they suck the sap from the leaves and shoots, but they also infect your plant with fungus.

Fungal leaf spot can look like water-soaked dark brown or black spots on the leaves. Sometimes there is a thin yellow ring around the spots.

When the disease first takes hold, the spots are mostly the same size. But if the disease progresses under wet conditions, the spots grow, spread, and join together, and the whole leaf turns yellow.

The spots remain as speckles on the leaves under dry conditions.

Also Check: ZZ Plant Repotting: Detailed Guide (Plus 6 Important Repotting Steps)

Get Rid Of Fungal Leaf Spot On A ZZ Plant

Thankfully, it is quite simple to deal with fungal leaf spot, and there is no need for any harsh chemical fungicides. There are a number of highly effective organic measures you can take to stop the spread of fungal leaf spot.

First, use a pair of sharp, sterile pruning shears to cut off any badly damaged leaves.

Next, spray the whole plant with a copper-based fungicide. Do this once a week to keep the disease from spreading. Copper fungicide will not kill the leaf spot itself, but it will stop new spores from germinating.

Also, treat the plant with an organic bio-fungicide spray. Apply this to your ZZ plant once a week until you see no more spots reappearing.

Why Is There Mold At The Base Of My ZZ Plant?

It is quite common for houseplants to develop a fuzzy-looking mold on the soil surface. This is no cause for concern because it doesn’t harm the plant at all.

The mold is a type of saprophytic fungus which feeds on decaying organic matter in the soil.

While the mold itself is not a threat to the plant, it is an indication that the soil is too moist. It can be a sign that you are overwatering your ZZ plant or that the soil does not drain well enough.

Prevent Fungal Diseases In ZZ Plants

When ZZ plants are properly cared for and healthy, they are far more resilient to fungal issues.

Here are some tips to prevent fungi from infecting your ZZ plant:

  • Be cautious not to overwater your ZZ plant. They like to be kept on the drier side. Ensure that most of the soil in the pot dries in between watering.
  • Make sure that your plant has adequate air circulation around it.
  • Keep your ZZ plant in a humid but not too humid environment. They need at least 40% humidity to grow healthily. However, excessive humidity can lead to fungal diseases because spores can stick to the leaves more easily.
  • ZZ plants do not need to be fertilized very often. Feed them sparingly.
  • If you notice insect pests on your ZZ plant, address them immediately. They can be vectors for fungal spores.
  • Avoid getting the leaves of your ZZ plant wet. Drops of water on the foliage attract airborne fungal spores.
  • When potting up your ZZ plant, always use a fresh bag of potting soil. Old, contaminated potting soil is a major cause of fungal problems.
Water drops on a leaf


While ZZ plants are generally hardy, low-maintenance houseplants, they can succumb to fungal diseases. When ZZ plants are overwatered or growing in soil without adequate drainage, they are far more susceptible to fungal rhizome or stem rot and leaf spot.

The good news is that if you catch these diseases early on, you can easily save your ZZ plant. If it is too late and the fungal infection has turned your ZZ plant into a mushy, drooping mess, you may need to salvage the healthy parts to propagate and throw the rest of the plant and the soil away.