Houseplant Care

How to Control Common Houseplant Pests

There are a number of pests that can infect your houseplants from time to time. These are mostly sap-sucking insects and fairly easy to control. Have a look at these five different pests that might be infecting your houseplants and how you can easily control them.

Although pests on houseplants aren’t as prolific or common as the pests you might find on your plants outdoors, they do still occur. And when they do, you want to control them as quickly as you can to avoid any damage or them spreading to other plants.

Wherever possible, it’s a good idea to use organic controls for your houseplants to limit the amount of chemicals that you spray in your home. In saying that though, we’ll be discussing both eco-friendly controls as well as chemical controls so that you can have the choice.

Here are 5 common pests that you are likely to find on your houseplants.

1. Aphids

Although more common on your outdoor plants, aphids can make their way inside and feast on your precious houseplants. Aphids are sap-sucking insects that generally attack new growth. They’re quite small and can be green, black or gray in color.

You’ll usually find them on the undersides of leaves or on new flower buds. Because they tend to congregate in large clusters, they’re very easy to spot. Aphids also exude a sticky honeydew type substance that is easy to spot on the lower leaves.

If left uncontrolled, leaves and young stems will start to turn yellow and new growth will become distorted.

Treatment

Aphids are fairly easy to control with a spray made from dish detergent mixed with water in a spray bottle. Spray the plant liberally making sure to cover the aphids with the mixture. What this does is coat the aphids so that they die.

Leave the mixture on the plant for around 5 minutes and then wash it off. You can do this in the shower or even under some running water in the sink. You may have to repeat this a couple of times to ensure you’ve removed all the aphids.

If you need something a little stronger, you can use a proprietary product that contains pyrethrin or neem oil. You’ll usually find this in convenient spray bottles at your local garden center.

2. Mealybugs

Mealybugs, like aphids, are sap-sucking insects. They’re small, white and look slightly furry. Mealybugs also cluster together and are really easy to spot. At a quick glance, they look like there’s some cotton wool on your plant.

If you don’t get rid of them, the leaves of your plants will eventually turn yellow and drop off.

Treatment

You can easily dislodge the offending mealybugs by spraying them with water. In the shower is best. If there are only a few, you can gently scrape them off, wearing gloves of course.

Otherwise, you can use the same dish soap spray method that we discussed for controlling aphids.

For a chemical control, look for a product that contains natural fatty acids or a surfactant.

3. Red Spider Mites

Red spider mites are one of those houseplant pests that are quite difficult to control. They’re actually related to spiders and do, indeed, spin tiny webs all over your plants. However, they feed on the sap of the leaves. The tiny webs are there to protect an entire colony of spider mites.

You should be able to see the webbing on your plants if there are red spider mites present. However, the most prominent symptom of a red spider mite infestation is that the leaves will start to look mottled with tiny brown dots. This is actually a form of necrosis in the leaf.

Treatment

Because red spider mites hate water and humidity, placing your plants in the shower once a week will gradually reduce their numbers. Make sure you use tepid water. On the days between showering, mist your plant daily to increase the humidity around it.

If you have a very large infestation that you can’t get under control, it is possible to purchase predatory mites that feed on red spider mites. These predatory mites are known as Phytosieulus persimilis.

If you want a chemical treatment, choose a houseplant insecticide that contains a surfactant or natural fatty acids such as white oil.

4. Scale Insects

Scale is another insect that can be a little difficult to control. In fact, if you have scale on your plants, they may not look like insects at all. This is because these insects have an outer shell that is quite hard and adheres the insect to the plant’s leaves and stems.

Initially, these look like tiny brown nodules on the stems and leaves of your plants. Scale also produce a sticky, honeydew substance that will stick to your plant. This eventually turns black and looks just like a sooty mold.

Treatment

Scale insects can simply be rubbed off if there are only a few. But, because the young are mobile, you’ll have to be vigilant for a couple of weeks to ensure that you get them all.

Another thing you can do is dab a little alcohol onto each scale insect with a cotton swab. The alcohol will dissolve the insects. Alternatively, using the soapy spray that you use on aphids will soften the hard shell of the scale insects. Then you can simply wipe them off with a damp cloth.

If you’re after something a little stronger, try an insecticide containing permethrin or malathion. However, don’t use these chemicals on ferns because of their sensitivity.

5. Fungus Gnats

Fungus gnats are those tiny little fly-like insects that you often find on fruit that’s been sitting around for too long. They’re actually not harmful to your plants but they are a nuisance to have in the house.

You’ll find fungus gnats flying around your plants, but their larvae exist in the soil just under the top surface. They feed on organic matter and love moist soil.

Treatment

To encourage fungus gnats to leave your plants, make sure that you remove any dead foliage that’s ended up in the pot. You’ll also want to let the surface soil dry out. Consider watering your plants from the bottom instead until the gnats have disappeared.

You can also use yellow sticky paper that you can buy from your local garden center.

If you want to use a chemical control, try a spray containing Pyrethrin. You’ll have to do a follow up spray once the larvae emerge from the soil.

Final Thoughts

Houseplant pests are not as common as the ones that you might find on your plants outdoors. However, they do need to be controlled if you find them.

Most houseplant pests are sap-suckers and can easily be controlled with a spray containing dish detergent and water. You might need to apply this more than once but you should eventually rid your plants of these pests.