While I find spider plants (Chlorophytum comosum) generally easy to care for, they are still susceptible to damage from numerous pests and diseases. In my experience, these include sap-sucking pests as well as multiple diseases. To keep your plant healthy, provide the proper environment and treat pests and diseases as soon as you notice them with a suitable pesticide or insecticide solution tailored to the specific problem.
Bacterial Leaf Spot
If you notice dark leaf spots with a sticky ooze, your spider plant may suffer from bacterial leaf spots. This disease often occurs in areas with poor circulation or high humidity.
To prevent this disease, avoid splashing water on your plant’s leaves when you water. Additionally, provide your plant with good airflow.
Removing the infected leaves and improving circulation will typically eliminate this problem and is my preferred form of pest control.
This fungus covers your spider plant with a powdery coating. It’s most likely to occur under humid conditions with poor airflow.
To stop the spread of powdery mildew, I improve airflow using a fan. You can treat the fungus with a copper spray if your plant is severely impacted.
Numerous tiny, sap-sucking pests attack spider plants. All of these pests use their piercing mouthparts to suck out plant juices.
These pests may appear in any environment, but they may occur more often in hot and dry environments.
Keep an eye out for the following sap-sucking pests.
- Aphids are 1/16 to 1/8 of an inch. They may be green, yellow, black, red, gray, or other colors.
- Spider mites are 1/50th of an inch. Since they are so small, you might see their spider-like webs before noticing the pests themselves.
- Thrips are oblong pests that range in size from 1/20 to 1/2 of an inch. Their colors vary from light yellow to dark brown.
- Mealybugs resemble tiny pieces of fluffy, white cotton.
- Whiteflies have two distinct white wings. They may be 1/16 to 1/10 inches long.
Small numbers of these pests generally won’t cause much damage to spider plants, but larger infestations can cause new tissue to die and lead to yellow or brown spider plant leaves or overall wilting of the plant. These pests can be especially harmful to the spiderettes that form on the ends of plant leaves.
As these pests feed, they secrete a sticky substance known as honeydew. While the honeydew itself won’t harm your spider plant, it can lead to the formation of sooty mold. This dark mold can inhibit photosynthesis and lead to plant decline.
I treat these pests by using insecticidal soap, horticultural oil, or neem oil. While these options generally curb pest numbers, you can turn to synthetic pesticides if you’re still having problems.
While fungus gnats generally don’t cause serious harm to spider plants, they can quickly become annoying. Over time, the tiny larvae may cause noticeable damage as they feed on plant roots.
If you’ve never dealt with fungus gnats, they look like small flies. Like many small insects, they have a short lifecycle, so their numbers can rapidly increase.
The adults lay eggs on the surface of moist potting soil. Once these eggs hatch, the larvae feed on organic matter in the soil and plant roots. After about two weeks, the larvae emerge as adults.
It’s easier to prevent fungus gnats than it is to treat them. Avoid overwatering your plants, as fungus gnats favor wet soils. Additionally, check all new plants for these pests before bringing them into your home.
If you’d like to treat the fungus gnats, you can use yellow sticky traps or the bacteria Bacillus thuringiensis israelensis (Bti).
Pesticide and Insecticide Options
Oils like mineral oil and canola oil can be used to suffocate soft-bodied insects. These products can effectively treat aphids, thrips, spider mites, and more.
For effective control, you must thoroughly coat insects with horticultural oil. Apply every week until the pests are diminished.
This horticultural oil from Bonide (via Amazon) comes pre-diluted in a spray bottle.
While neem oil is a type of horticultural oil, it deserves its own recognition. This product is made from the seeds of the neem tree.
While it can kill soft-bodied pests by suffocating them, it also has another mode of action. Neem oil contains compounds such as azadirachtin that disrupt an insect’s natural life cycle.
When applying neem oil, mix the oil with water following product directions. Use a spray bottle to apply the mixture, and aim to make direct contact with the pests.
Monterey Neem Oil is available in both ready-to-spray forms and concentrated solutions.
Insecticidal soaps work similarly to horticultural oil. They coat soft-bodied insects, causing them to suffocate and die.
While you can use regular dish soap to treat pests, the additives in these soaps may harm your spider plant. Therefore, the best option is to use a product such as Bonide insecticidal soap.
When you spray your spider plant, you want to make sure you thoroughly coat all sides of the leaves.
When pesticides are made from artificial compounds rather than naturally-derived elements, they’re known as synthetic pesticides. If you choose to use synthetic pesticides, it’s essential to be aware of significant differences between products.
Some synthetic insecticides will affect all types of insects, while others will only harm a certain insect family or genus. The toxicity of these products also varies between products.
Pest outbreaks on spider plants can generally be treated without synthetic pesticides. With that said, if you choose to use synthetic options, make sure you follow product instructions.
While sticky traps are often used to monitor pests, you can also use them to trap flying pests such as aphids and fungus gnats.
Yellow sticky traps (via Amazon) can capture whiteflies, thrips, fungus gnats, and other pests.
How to Use Pesticides On Spider Plants
Before we explore how to use pesticides properly, we will cover some basic information.
First, understand that insecticides are a type of pesticide that impacts insects. While all insecticides are pesticides, not all pesticides are insecticides. The broader term pesticide may also refer to fungicides, herbicides, and molluscicides.
When you look at insecticides, you can break the products down into two main categories: organic and synthetic. Organic products are produced from naturally occurring compounds such as bacteria or plant extracts. Synthetic insecticides contain materials that are manufactured.
While many people think only synthetic insecticides can harm humans and the environment, organic insecticides can also have adverse effects. That’s why you must follow product instructions.
Gloves – even though spider plants aren’t considered toxic to humans, it’s prudent to wear gloves throughout any extended houseplant care project.
Before applying an insecticide to your spider plant, think about the following.
- Mode of action: Insecticides may work by suffocating insects, stopping feeding, disrupting molting, or via other mechanisms. Understanding the mode of action will provide you with information such as if you need to spray insecticide directly on the pests.
- Target pests: Not all insecticides will impact all pests. Similarly, some products will impact all insects, even the good ones. In general, it’s best to choose a product that harms the target pest but nothing else.
- Application frequency: The mode of action also impacts how long an insecticide will take to work. This will determine how often you need to apply this product.
The most important note is always to apply insecticides following product instructions. Also, be cautious with recently propagated spider plants whilst they are taking root.
Managing Spider Plant Pests & Diseases
Preventing pests and diseases is often easier than treating the pests. One of the best ways to avoid problems is to provide your spider plant with the proper environment and care.
Spider plants like well-draining and moderately moist soil. With that in mind, water only when the top few inches of soil is dry.
Position your spider plants in an area with lots of bright, indirect light. This area should also have an air temperature between 60-85ºF and moderate humidity.
In addition to providing the proper environment, you should also regularly check your plant for problems and consider fertilizing your spider plant in spring and summer to boost the nutrient base (this is also the best time to consider repotting your spider plant and pruning). If you notice a pest or disease, treat the problem ASAP.
For more, see our ultimate guide to spider plant care at home.
Spider Plant Pests and Diseases – The Final Word
Now that you know some of the most common spider plant pests and diseases keep an eye out for these unwelcome guests. As long as you swiftly treat the problem, your spider plant will return to good health.