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While having the correct light levels and watering properly are two of the most important steps in growing healthy indoor plants, houseplant growers also have to constantly monitor their plants for signs of pests. There are many types of houseplant bugs, and arming yourself with a little information goes a long way toward preventing or eliminating an infestation.
Preventing houseplant pest infestations
Certain houseplants are definitely more prone to pest issues than others, but houseplant bug problems are often prevented by following a few simple steps.
- Carefully inspect all new plants before bringing them into your home. Many types of houseplant bugs piggyback their way into your house from the nursery where the plants were grown. Before buying new plants (or taking in “strays” from friends and family), be sure to examine the plant from top to bottom, looking on leaf undersides, along the stems, and even in the soil for signs of the common houseplant insect pests I’m going to introduce you to below.
- Even if you think a new plant is pest-free, it may have pest eggs or young pests that you can’t yet see. Before putting any new houseplants with ones you already have, put it in solitary confinement in a separate room for a few weeks. Watch it carefully for signs of houseplant insect pests and only put it in close contact with other plants after it’s been confirmed to be pest-free. You can also place a few yellow sticky cards just above the top of the plant. Many pest insects are attracted to the color yellow, and they’ll quickly get trapped on the card. Check the card every few days for any insects. If you have some on the card, you probably have many more on the plant itself.
- Before moving them back indoors, do a “detox” on any houseplants that have spent the summer outside. While most houseplants love to be outside during the warmer months, they often come back inside with several different types of houseplant bugs hitch-hiking on them. The day before moving houseplants back indoors, spray the entire plant – including the lower leaf surfaces and stems – with a sharp stream of water from the hose, using a spray nozzle that emits a forceful spray. This is often all that’s needed to dislodge any pests before moving the plant inside.
- Keen observational skills definitely allow you to control many types of houseplant bugs before their populations explode. Examine plants weekly throughout the year, checking for both the insects themselves and signs of their damage.
- Another sign that indicates you may have one of several different types of houseplant bugs is the presence of a sticky substance on the plant itself, or on the surface of the table or floor beneath the plant. This shiny, sticky substance is called honeydew, and it’s the excrement of several different pests, including almost all of the houseplant pests mentioned below. The presence of honeydew is a clear sign of pest issues.
Types of houseplant bugs
The warm, consistent temperature of most homes is ideal for rapid pest breeding. Plus, without ladybugs, parasitic wasps, and other beneficial insects in your home to keep pests in check, houseplant insect pests can go from numbering just a few to an all-out infestation in no time flat. Here are five of the most common types of houseplant bugs and what to do about them.
Adult fungus gnats are super annoying. These minuscule black flies are the classic example of a nuisance pest. When an infested plant is disturbed, a cloud of tiny flies lifts off the soil. Mature gnats life for about a week, and although they’re a pain, they don’t damage your plants. Neither do the larvae, who largely feed on the fungi that naturally grows in potting soil. Because the eggs and larvae need water to survive, fungus gnat infestations are frequently the result of overwatering. A simple reduction in watering is often all that’s needed to control this common houseplant pest. But, if that doesn’t do the trick, a product like Gnatnix will definitely take care of the problem.
Another of the more common types of houseplant bugs, scale is sometimes difficult to spot. There are many different species, each with a unique appearance, but the most common houseplant pest scales look like little bumps and are found along the stems and on leaf undersides. Scale insects often have a hard, shell-like covering that makes them difficult to spot and control. They can be gray, black, brown, or even fuzzy. Most scales leave behind the honeydew I mentioned above, so if you see a shiny glaze on the plant, check it for scale. When it comes to houseplant bug problems, scale is probably the most difficult to control. I like to wipe them off my plants with a special cotton pad (like these) soaked in isopropyl rubbing alcohol. Physically wiping the pest off the plant multiple times over the course of a few weeks offers the best control. But, another option is to use an organic, neem-based pesticide. Take the plant into a garage or outdoors to apply it, and be sure to follow label instructions.
This common houseplant pest does not survive freezing winter temperatures, so it’s typically troublesome outdoors only in southern regions. But, whiteflies are one of the most problematic types of houseplant bugs because when they’re indoors, the insects are protected from freezing temperatures and their populations can grow quite rapidly. Whitefly issues frequently originate via a plant purchased at an infested greenhouse, which makes a careful inspection of any new plants extra important. These tiny, white, moth-like flies are found on leaf undersides and will quickly fly off the plant when it’s disturbed. Since whitefly reproduce so rapidly, their sap-sucking behavior can leave plants wilted, and with stunted growth and yellow foliage. Whiteflies are readily trapped by placing yellow sticky cards just above plant tops. Applications of insecticidal soap and horticultural oil are also effective. Since all three of these products work best when they contact the insect pest directly, try not to disturb the plant when applying, and be sure to cover both upper and lower leaf surfaces.
Though they’re small in size, aphids can cause big problems. Of all the types of houseplant bugs discussed here, aphids are the ones I encounter the most frequently on my own houseplants. Tiny and teardrop-shaped, aphids can be black, green, red, yellow, or brown. Sometimes they have wings and sometimes they don’t, but they’re most often found grouped together on new growth or on the undersides of leaves. As they suck plant sap through their needle-like mouthparts, aphids cause deformed and stunted plant growth. Small infestations are easily wiped off of plants with a soft, plant-friendly cloth soaked in water, but as with all types of houseplant bugs, when there’s a big infestation, other measures may be warranted. Aphids can also be controlled organically with hot pepper wax, horticultural oil, or insecticidal soap. Be sure to apply these products so they come in direct contact with the aphids themselves for the best results.
There are many types of houseplant bugs, but spider mites may just be the ones with the biggest “heebie jeebie” factor. Actually, these guys aren’t bugs at all. Instead, they’re close relatives of spiders. These teeny-tiny houseplant pests cause major issues, not just for plants but also for the homeowner facing the infestation. Though you can barely see them without the help of a magnifying glass, once you know they’re in your house, it’s hard to get them off your mind. Spider mites spin a fine, silky webbing, and collectively, they can cover the entire plant with it. If you look carefully, you’ll see tiny specks crawling around on the webbing; those are the mites themselves. But, before you toss your spider mite-infested ivy or palm plant into the garbage, there are a few steps you can take to get this common houseplant pest in check. First, take the plant outdoors or into the shower and “wash” it off with a spray of water. Spider mites are tiny and are easily washed off the plant. Be sure to rinse both upper and lower leaf surfaces. Then, after the plant has fully dried, use a light-weight horticultural oil to smother them. Reapply the horticultural oil every 10-14 days for two more applications for the best control.
Though there are a handful of other indoor plant pests that may occasionally prove problematic, these five types of houseplant bugs are by far the most common. But, by following the five preventative steps featured at the beginning of this article and using the suggested mechanical and organic product controls, you’ll be able to keep most of these little buggers from causing any real issues.
Remember, arming yourself with a little information goes a long way toward growing healthy, pest-free houseplants. Be smart about your choice of plants. For apartment dwellers, our list of the best houseplants for small spaces offers plenty of great plant choices. Healthy houseplants are better able to fend off pests, too. We’re sure you’ll find our guide to houseplant fertilizer basics very useful, too.
More posts about managing pests
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- How to prevent pests in the garden: 5 strategies
- Identifying garden pests: How to figure out who is eating your plants