Houseplant bugs can quickly go from a small nuisance to a huge problem. Houseplant pests can kill the infested plant and move over to new indoor plants in no time at all. Different pests will target different types of houseplants, but there are some insect species in the UK that aren't fussy and won't care whether you've got a Swiss Cheese Plant or a Boston Fern. It's all lunch to them!
Organic pest control is an option, but before you buy gallons of insecticidal soap, let's make sure that you're using the right bug control method. Some plants won't survive an insecticidal spray, while other plants react better to milder methods.
Below, we'll cover the most common bugs in the UK and the best method for eradicating each.
Most common houseplant pests
From infecting the potting soil and attacking plant roots to sucking plant sap from the fresh new stems of young plants, these pests are evil!
In your home, without natural predators (e.g., the humble ladybird) to protect your colourful or evergreen plant foliage, these pests can thrive. Here are 6 bugs to keep an eye out for.
Fungus gnats
Adult fungus gnats are actually flying bugs - they are dark in colour and will buzz up in a big cloud when you disturb the plant. Unfortunately, you probably won't spot infection of soil gnats until they reach an adult age in their cycle. Thankfully, the adult gnats don't do too much damage.
The fungus gnat larvae feed on decaying organic matter and plant roots - they're also known as soil gnats as a result. Like microscopic worms, you won't even notice the larvae until it's too late.
This pest thrives in moist, warm conditions so the main method for removing this pest includes dehydrating the soil. The best ways to get rid of fungus gnats include:
- Hanging sticky sheets to catch the adults before they lay more eggs.
- Placing dryer sheets around the plant to dry out the soil.
- Use diatomaceous earth on the soil surface, to dehydrate the larvae and thus kill them.
- Using a neem oil solution as you water your plants (learn more about this below).
Psst. At Gardeners Dream we sell all our indoor plants in sterile potting soil so you needn't worry about bringing fungus gnats into your home!
Aphids
An aphid infestation, inside or outside, is a nightmare. They attack beloved plants and lay eggs in staggering numbers.
This houseplant pest can be grey, yellow, white, or black in colour. These soft-bodied insects cover the entire plant very quickly. Due to the speed at which these common pests spread, it can be difficult to control aphids.
Isolate your infected plant as quickly as possible to stop the tiny bugs from jumping ship. You can also try these methods to remove them:
- Soap wash or spray with a soap solution or insecticidal soap.
- Repeated washing and spraying, as aphids are persistent.
- Moving the plant to an outdoor location so aphid predators can reach it.
- Water spray - literally give the plant a shower to wash the aphids off.
This is best for sturdy houseplants that can handle a strong stream of water, such as the Rubber Plant. Just make sure that the soil can drain freely, so you don't waterlog your plant.
Mealybugs
Mealybugs suck plant sap from your house plant. These tiny white bugs can cling to branches and lower leaf surfaces, slowly sucking the life from your plant. These bugs tend to stick on the joints of branches and leave to reproduce, appearing as white cotton buds (not to be confused with the webbing of spider mites, which you can read about below).
Although small and easy to spot, mealy bugs are one of the more serious pest infestations. Often the plant damage caused by mealy bugs is irreversible. The best ways to remove or control mealybugs include:
- Removing and destroying infected branches.
- Manually rubbing the bugs with rubbing alcohol.
- Spraying heavier infestations with both soap and neem oil.
The Jade Plant is particularly susceptible to mealybug. Many plants that have a serious infestation are beyond saving, so it's key to catch mealy bugs before they can multiply.
Scale insects
Scale insects are another pest that likes to suck plant sap. These houseplant insect pests are incredibly hard to get rid of and even though they are tiny insects, they can bring down sturdy plants in a matter of days - leaves turn yellow and droop.
Affected plants will be covered in these waxy oval-shaped insects that reproduce quickly. If you catch the insects while they're still growing, they're easier to remove. The adults, however, are a real pain. Along with mealybugs, they are a nightmare to get rid of.
Try these methods:
- Remove leaves and side shoots that have succumbed entirely to scale insects.
- Use chemical control for growing insects - insecticide or soap will kill the young ones.
- Use a brush or sponge to dislodge the adult insects, as their tough waxy shell protects them from soaps and sprays.
- Once dislodged, coat the plant in neem oil to prevent new waves of bugs from clinging on.
- Continue physically removing scale insects until they're all gone.
Plants that are more tree-like and have a rough, sturdy stem are more likely to survive a scale infestation - check out the Dragon Tree as an example.
Spider mites
Spider mites are tiny mites that leave tell-tale webs on growing plants. The spider mites themselves are no larger than a pinhead. They live on the upper and lower surfaces of leaves, but you will usually spot their webs left on stem and leaf joints first. You may also find that your foliage turns yellow and droops - a common sign of an insect infestation.
These common houseplant pests can slowly suck the life out of growing plants. Thankfully, they tend to be more manageable than scale and mealy bug problems. To deal with spider mites, you can try:
- Spray pesticides or any soap substance all over the plant to dehydrate the mites.
- Wipe the leaves gently to remove bugs directly.
- Repeat regularly until the mites and their webs are gone.
Spider mites are one of the smallest insects you can get on your plant. They don't require much force to remove (unlike scale insects, for example). Try to be gentle and let your soap get to work, so you don't end up damaging your plant in the process.
You may find spider mites on your indoor plants or greenhouse vegetables.
White fly
Whiteflies may take a while to infect a plant outdoors, but indoors these tiny flies multiply at an incredible speed. Attacking nearly all types of houseplants, it is tough to control whiteflies and stop them from spreading to new plants.
Like all the bugs we've mentioned, there are some ways to control them and get rid of them. However, you also need to know when it's time to let go of your plant and just buy a new one!
If you just can't let go, try eradicating white flies by:
- Applying sticky papers to some leaves and stems to remove the bulk of the population.
- Spraying the flies directly with soap insecticide - direct contact must be made.
- Focus on spraying the undersides of leaves, where the larvae grow.
- Repeat weekly until all whiteflies are gone.
With no natural predators inside, whiteflies get out of control fast. They are also more common on certain plant varieties, such as the ivy varieties including Devil's Ivy.
Action is the best defence!
Certain pests are difficult to remove and will utterly destroy a delicate new plant. That's why we believe offence is the best defence when it comes to common houseplant pests. Preventing pests from taking hold of your plants may include:
- Placing gravel or similar product on the soil surface, to prevent fungal infections and decay.
- Ensuring your potting mix drains well and doesn't stay too moist.
- Thoroughly clean new equipment and pots with soap and water to remove any pest larvae before using them for your indoor plants.
- Placing yellow sticky traps nearby during the height of pest season (summer) or when you've spotted suspicious insect activity in your home.
- Inspect each plant regularly to catch insects before they can really become a problem and spread.
5 Ways to remove pests from an infested plant
Now that we have identified some of the most common pests and how to remove them, let's take a closer look at the different methods we've mentioned. This section will explain how each method works and how to apply them. Don't hesitate to reach out to our horticulturalists if you'd like to quiz us and learn more!
1. Insecticidal soap
Insecticidal soap will get rid of most houseplants' problems. Wiping your plant leaves with soapy water can literally remove the pests and their larvae.
Soaps can work in a few other ways too:
- They leave a soapy residue on the surface of your plant, preventing bugs from getting a good grip on it,
- The detergent you use can dry out any insects it touches as the product dries,
- Many shop-bought insecticidal soaps also contain insecticides.
You can find insecticidal soap that's organic, using natural insecticide ingredients such as black pepper or rosemary, or chemical versions that are a bit stronger. Alternatively, you can make your own. The basic recipe for insecticidal soap is dish soap, water, and vegetable oil in a spray bottle.
Insecticidal soap works best on spider mites and whiteflies, being most effective when the soap directly hits the insects. It is less effective on fungus gnats (beneath the soil) and stubborn scales.
2. Neem oil
Neem oil is an oil made from the seeds and fruits of the neem tree. Growing natively in India, oils produced from this tree are widely used in agriculture and medicine. Neem's popularity as a horticultural oil is due to its natural insecticide properties.
The oil has a pungent garlic-like aroma and has numerous benefits:
- It can be applied to plants and even their fruits - it's non-toxic and edible.
- It doesn't leave toxic residue or chemicals in the soil as it washes off.
- It's safe for any wildlife or household pets that encounter your plants.
- It can also prevent mildew as well as kill and ward off pests!
When mixed with water and absorbed by your plant through the roots, the compound will be in the plant sap. As a result, any pest that feeds off plant sap will consume the neem. This stops their reproduction and discourages feeding.
You can also apply neem oil directly to the foliage of the plant, to target pests like spider mites. The oil can clog up the insects and prevent them from breathing, thus killing them.
When applying neem oil, ensure that you keep the plant out of direct sunlight as it can cause foliage burn.
3. Rubbing alcohol
Rubbing alcohol can get rid of common pests such as scale and mealybug, which may be stubborn enough to resist insecticidal soap.
Apply alcohol to the leaves and stems using a cotton swab, directly rubbing it on the insects to remove them. We recommend combining alcohol with insecticidal soap, to target both the adult and larvae of the insect on your plant.
Furthermore, the scent of alcohol is a natural deterrent for further insects that might want to make your lovely houseplants their home!
Be careful with this method, as too heavy a hand can dislodge flower buds and cause more damage. Alcohol will also dehydrate plant leaves as it dries, so consider washing the leaves with water after removing insects with alcohol.
4. Soil insecticides
Insecticidal soap is great for targeting insects living on the surface of the plant. However, fungus gnats and other fungal infections begin life below the soil. As a result, you'll want a different method for dealing with larvae.
Soil pest control methods include:
- Diatomaceous earth, which dehydrates the soil.
- Soil drenchers and powders - these products are available to buy and can be safely incorporated into the soil.
- Homemade remedies to place around the soil - apple cider vinegar and yellow sticky paper traps will naturally attract fungus gnats as they emerge from the soil.
With soil-based pests, nearly all come up to the surface as gnats or similar to reproduce. Catch enough of the adults and this should stop the entire life cycle.
5. Environmental Changes and Additions
Insecticides aside, there are several ways that you can make the plant (and your home in general) an unpleasant place for insects to live.
- Removing or adding humidity. For most pests, dry conditions are unfavourable.
- Hosing down the plant - literally washing off the insects if possible. You don't always need to use soapy water.
- Sticky paper traps and other insect traps can be placed around your plants.
At Gardeners Dream, we recommend using a plant pot gravel too, to assist with drainage, protect the soil, and prevent fungal problems.
Tips for growing healthy indoor plants!
Whether you're nurturing your Monstera or propagating a Croton Plan, keeping it healthy and happy will ensure good growth and naturally deter pests.
Start with a plant pot that's the right size for your plant, the correct soil (not too sandy, not too dry), and good water to establish those plant roots.
For further advice on getting the most from your indoor pot plants, check out all our blog articles here at Gardeners Dream. Explore our full range of indoor plants too - there's free delivery over £50 to any and every address in the UK!
Shop Gardeners Dream now to grow your collection of indoor pot plants.
