Should you be worried if your house plant is covered in a sticky residue? The stickiness can be cleared with some mild cleaning. However, some cases may be a sign of something more serious. Below is a quick summary before we dive into the main reasons for sticky plants.
House plants in California often attract pests such as scales and mealybugs. These inconspicuous insects feed on houseplants leading to the secretion of a substance called honeydew.
So What Causes the Build of the Sticky Sap?
The sticky sap is referred to as honeydew. Houseplants secrete the substance when attacked by aphis, soft scale, and mealy bugs.
In general, plants contain many sugars but few proteins. However, proteins are an essential nutrient for insects. This explains why they consume a lot of plant juice to produce protein.
The insects eat vast quantities of sugar to maximize the ingestion of nutrition. In doing so, they convert plant sugars into various sugars.
The honeydew remains on the surface of the plant. It is also not uncommon for the honeydew to drop onto lower leaves.
As it accumulates, the sticky substance can drip onto objects under the house plant. Things under the plant include carpeting, furniture, and the floor.
Research shows that insects feeding on the same plant can produce various sugar mixtures. Aphids, for example, make the most complex combination of sugars in vast quantities.
The honeydew creates a snowball effect that attracts other insects such as ants and honeybees. It is worth noting that the sticky substance itself is not harmful to the houseplants.
Sticky plants with honeydew residue are vulnerable to insects that can weaken their structure. Moreover, the sticky honeydew layer restricts photosynthesis, which can inhibit growth.
Another disadvantage of honeydew is that it creates ideal conditions for the proliferation of fungi.
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Houseplants also Secret Sticky Nectars
It is not uncommon for some houseplants in California to secrete sticky substances.
This is mostly done to attract certain types of pests or ward others off. Houseplants contain a network of extra floral glands responsible for secreting nectar.
These glands secrete nectar that draws in ants to protect the plant from pests. This results in a symbiotic relationship where the nectar is responsible for the plant’s survival.
Houseplants in California may also secrete nectar to attract bees and butterflies. This phenomenon has been heavily studied by scientists and is known as pollination.
The long-term strategy of luring bees is to propagate the plant’s species.
Houseplants may also secrete nectar to repel unwanted pests that get too close to them. This nectar is unattractive to the particular pest and is forced to leave the plant.
Carnivorous plants may also produce nectar as insect bait to eat prey. In any case, if the sticky substance is allowed to linger on, it undergoes oxidation. This changes the appearance of the nectar into an unsightly brown hue.
Why Honeydew May Turn a Shade of Brown
The nectar may drop onto nearby surfaces, floors, carpets, and other objects. This can throw off the room’s overall appearance and look unappealing.
It is not recommended to leave the honeydew to linger on surfaces for too long. They will draw more insects, bacteria, and even pathogens. Fungi may build their colonies on the nectar and contribute to a darker appearance.
The honeydew may also trap dust and dirt, making the sticky look even more untidy. The sticky substance turns a shade of brown because the sugars are oxidized by air.
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Honeydew and the Life Cycle of Insects
Different insects have different life cycles. The three life cycle stages are the egg, nymph, and adulthood.
Eggs are mainly laid under the scale coverings of adult females. After hatching from their egg shells, the larvae crawl to a feeding site. These larvae are also known as crawlers.
The crawlers begin sucking the sap from house plants at the new feeding site. The insects may remain at the feeding site for the remainder of their lifecycle.
Even a small-scale infestation can damage otherwise healthy houseplants in California. Large-scale infestations can lead to stunted growth.
It is not uncommon for some infestation cases to lead to the plant’s death. Plant owners are recommended to keep pest infestations under check.
However, some pests, such as scales, are hard to control. This is because of the shell-like covering that protects them from insecticides.
Scales are only vulnerable to insecticides in the crawler stage of their life cycle. It is recommended to spray scale-infested plants with a houseplant insecticide every week.
Small-scale infestations may be dealt with by scraping individual scales by hand. A common remedy is to use alcohol cotton swabs to cover each scale.
In some cases, it may be impossible to treat scale infestations. It may be advised to discard these houseplants to protect nearby plants.
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Pest Identification and Extermination Strategies
Pests like brown scales and white flies inevitably lead to the buildup of honeydew. It is essential to deal with pest infestation before they weaken the plant.
However, using a one-size-fits-all extermination strategy is not advised to kill pests. Doing so could adversely affect the health of your houseplants.
A better approach is to identify the pest and devise an extermination strategy. The section below will look at houseplant pests you are likely to see.
Use this table as a quick summary.
| Type of Pest Infestation | Recommended Solution |
| Brown Scales | Spray with an insecticide (labeled for indoor use) |
| Whitefly | Use whitefly predators |
| Mealybugs | Spray with isopropyl alcohol (in mild quantities) |
| Aphids | Spray with essential oils |
Brown Scales
The brown scale belongs to the Diaspididae and Coccidae families. It is hard to notice these insects because of their small size.
Most people become aware of brown scale infestation when their plants become shiny and sticky. A closer inspection will reveal brown insects close to the plant’s veins.
The most common species of brown scale belong to the Coccus hesperidum L. family. They are tiny and don’t look like your average insect – to an untrained eye.
They have an oval shape, barely spanning 3 to 4 mm long, with flat bodies. Brown scales appear slightly domed when viewed from a different angle.
The color of the scale ranges from yellow-green to light gray. The female scale’s color will darken as she gets older. Scales may also be found in shades of yellow and amber.
It is important to clear brown-scale colonies as soon as you find them. They are resilient species that reproduce year-round.
The good news is that scales are relatively immobile. Here’s how to deal with them:
- Cover the plant’s soil with a plastic bag to catch falling scales.
- Find an insecticide that is specifically labeled for indoor use. Spray the insecticide on the plant once it becomes soapy.
- Use your fingers to pick off individual scales. Use a toothbrush for a more hands-off approach.
- You will notice that some scales may fall onto the plastic covering. Pick them up and dispose of them.
- Do not miss a spot because leaving even one scale could lead to a re-infestation.
- It is recommended to get a pocket magnifier to see scales more clearly.
- Remove the insecticide once you have cleared the plant from the scales. This is important because the insecticide will inhibit the plant’s growth.
Whitefly
It is easy to confuse whiteflies with white moths because they can fly. However, whiteflies are more closely related to scale and aphids.
They are capable of laying eggs while simultaneously ingesting juices from the plants. This causes the leaves to turn yellow and fall off prematurely.
Whiteflies will eventually weaken your plant and cause it to die. It is in your plant’s best interests to deal with whitefly infestation early.
Whiteflies are primarily drawn to the yellow color. The best way to catch them is by setting up yellow sticky traps.
Other strategies include adding a predator like a whitefly parasite or watering from a hose. Make sure to use a combination of the above techniques for the best results.
Mealybugs
Mealybugs belong to the Pseudococcidae family and feed on the nectar of most houseplants. These slow-moving, oval insects are covered with a white wax that is hard to miss.
Mealybugs can infest all parts of the houseplant, including its roots. They have a soft body with a relatively pink hue.
Mealybugs are usually found clustering on the underside of houseplants and are easily visible. Their favorite feeding site is stem tips, where the leaf meets the stem.
Common signs of mealybug infestations include stunted growth, wilting, defoliation, and a sticky substance.
On average, mealybugs can lay anywhere from 600 to 1000 yellow eggs. They may lay their eggs throughout the year. The female mealybug dies after laying eggs in 10 days.
The best way to treat mealybug infestations is to prevent them in the first place. Try to inspect all new houseplants for infestation. Return the plant to the supplier if they are infested.
You may have to destroy heavily infested houseplants because cleanup may be too costly. A common strategy to deal with mealybugs is to use mealybug destroyers.
Destroyers are a type of beetle that can effectively curb the mealybug population. However, this technique is only effective if you have an appetite for a low-level infestation.
The green lacewing is another mealybug killer that can be used for pest control.
It may be easier to control light to moderate mealybug infestation. Here are a few steps that you may try:
- Use alcohol swabs to remove all visible sightings of mealybugs.
- Use the cotton balls to clean the leaves thoroughly.
- Mix a few drops of dish soap with 1 cup of rubbing alcohol. Now pour the solution into the spray bottle.
- Spray the entire plant with the bottle, including the top, underside, and stems.
- Repeat the above steps a few months until the mealybugs are gone.
Using all the above methods is advised to deal with mealybug infestations.
Caution: Rubbing alcohol is effective at killing mealybugs. However, it could adversely affect the plant by breaking into its structure. Try what works for your houseplant.
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Aphids
Aphids are among the most common pests that can cause extensive damage to plants. They reproduce rapidly and can produce offspring without mating.
This allows aphids to multiply their population rapidly in a short amount of time. Aphid infestation may go undetected for a long time because of its appearance.
They are tiny with pear-shaped bodies that are invisible to the naked eye. Various species of aphids can appear in multiple colors, including white and gray. Some aphids may have a wooly coating.
The earliest stages of the infestation may be controlled using a powerful stream of water. A garden use can be used to shade off aphids from your house plants.
This step isn’t recommended for fragile plants, especially smaller house plants. However, the strategy works well if you use a high enough water pressure.
A small-scale infestation may be dealt with by hand. Put on your garden gloves and knock the aphids off of leaves and stems. A common strategy is to cut off the affected area of the plant by pruning.
Consider using natural predators like lady beetles to eat large populations of aphids. Here are a few tips to improve the effectiveness of ladybugs:
- Lightly water your plants before releasing ladybugs to keep them hydrated
- Release them in the early morning or evening for better results
- Repeat the above as many times as needed
A fool-proof strategy that kills aphids without affecting the houseplant is to spray essential oils. Here’s how:
- Add a few drops of essential oils like rosemary, thyme, peppermint, and clove with water.
- Mix the solution in a spray bottle.
- Spray the solution on affected pants to deal with aphids, their nymphs, and eggs.
Wrapping Up – Prevention is Better Than Cure
Most strategies mentioned above will also cause some degree of harm to plants. This is why it is recommended to use preventive measures to keep pests at bay.
Here are a few things you can do:
- Always clean your pots and potting soil
- Inspect new houseplants before buying them
- Isolate affected house plants from other plants for a few days
- Don’t allow other plant leaves to touch the leaves of new plants
So how did you deal with a pest infestation? Let us know your strategies, and we might update this space with your suggestions.
You may like the following houseplants articles:
- Why Are My House Plant Leaves Turning Black?
- Why Are There Little Flies in My House Plant?
- How to Treat House Plant Fungus
- Why Are My House Plant’s Leaves Turning Brown?
- Types of House Plants with Large Leaves
Hi! I’m Sophia, and I love plants – especially an expert in growing house plants. I stay in Chicago, United States of America, and through my blog and social media platforms, provide tips and tricks on how to grow healthy, vibrant plants indoors. Check out more here.