It’s a cold February morning in Woodstock, Ontario and you just watered your Hibiscus plant, which is sitting in my window soaking up the winter sun.
As you go to tend to another plant, you brush up against your prized Hibiscus, only to feel something feel something sticky.
A closer examination reveals a slew of tiny, green, soft-bodied round creatures!
What do you do!?
Luckily, I know how to get rid of these (and other) pesky houseplant pests – but before I disclose the solution, let’s address the problem of insect pests on indoor plants in more detail, shall we?
First things first.
Just how did these pests get into my home in the first place?
In most cases, the problem of pests on indoor plants begins long before you actually witness them. For instance, back in October, I trimmed back my Hibiscus plant, prior to transplanting it for the winter, and in doing so I made sure to spray it with a soapy water solution to kill any bugs that might have been present at the time.
As a result, my Hibiscus was thriving, with plenty of new, lush growth. However, just a few months later I began to notice the tiny insects.
Unfortunately, these pesky critters must have laid eggs on my Hibiscus while it was still outside – and a spray with soapy water won’t kill the eggs. On top of that, my warm living room was the ideal environment for these pests to multiply, and there are no natural predators inside our home to keep them under control – hence their rapid growth.
In the case of my Hibiscus, the culprits were “Aphids”, however, as you’ll soon learn there are a number of common pests that can infect your houseplants.
Pest #1: Aphids
As soft-bodied insects, Aphids often take on the colour of the plant – making them difficult to spot. But if you look closely you may find them at the growing tips of the plant shoots.
Aphids use their beak-like snout to suck plant juices. Although they can be hard to see, you’ll probably notice the sticky residue they emit as they feed. If they are left to multiply, your plant will soon be covered in a sooty mould.
Luckily, aphids are fairly easy to deal with. They can be killed by spraying them with soapy water, followed by at least two follow-up sprays a week apart to keep them under control.
Pest #2: Spider Mites
Spider mites may technically not be insects, but we still don’t want them setting up home on our houseplants!
Spider mites can be very tricky to spot because they are so tiny. You may notice very fine white dots on the leaves of your plants, and a general yellowness and lack of vigour. In advanced infestations, you will see very fine webbing.
Spider mites attack the underside of leaves. If you suspect your plant is under attack, examine the underside of a leaf for small yellow or red dots that seem to be walking around.
Spider mites prefer plants with thin leaves, and they thrive on dry air – just like the air most of us have indoors during the winter months. They dislike humidity, so leafy houseplants that are underwatered are especially vulnerable.
Since spider mites are mobile, it’s important to isolate an affected plant. Then soak the plant with soapy water, making sure all leaf surfaces are covered – especially underneath the foliage. Follow-up weekly.
If you have a houseplant that seems to be prone to spider mites, use a spray mist a few times a week as a preventative.
Pest #3: Mealy Bugs
These bugs don’t look like a typical insect.
In fact, they look like bits of cotton – but don’t be fooled! Inside the ‘cotton’ is a small insect that sucks on the shoots of your houseplant.
Luckily, these sneaky culprits are easily removed by rubbing them out with a Q-tip soaked in rubbing alcohol.
Pest #4: Fungus Gnats
If you notice tiny flies around your houseplants, be on the lookout for fungus gnats. Much smaller than houseflies, they are harmless to humans – although they can be annoying.
Fungus gnats like to lay their eggs in wet soil, and their wormlike larvae eat plant roots. In heavy infestations, the larvae can kill newly-sprouted seedlings.
Since fungus gnats thrive on moisture, they are easily prevented by not over-watering your houseplants. If they do become a problem, simply let your plants dry out and place a small dish of water mixed with some dishwashing liquid as a decoy.
Now – back to the aphids on my Hibiscus.
After mixing one-part dishwashing liquid and 19-parts water in a spray bottle, I give my plant a good soak.
Looking closely, I can see the aphids are agitated. In just a few minutes, they will be dead. Within a week I will respray my plant to kill any unhatched eggs.
Here’s to keeping the insects outside, where they belong!
If you have a question about houseplant pests, the experts at Van Dyk’s Greenhouses are here to help. Email us at email@example.com