Surviving Houseplant Pests: What Actually Worked for Me

TL;DR

Thrips: soap or NeemAzal alone isn’t enough. What broke the cycle was a flupyradifurone spray (Sanium System), repeated after a few days.
Spider mites: washing and spraying works on the ficus, not on alocasias. Today they’re my worst pest.
Aphids: washing the leaves and spraying with NeemAzal or soap is usually enough.
Fungus gnats: bottom watering and letting the top of the substrate dry out helped most.
Springtails: harmless, and they disappear once I stop overwatering.

This isn’t a botany handbook, just my notes from keeping a mixed indoor collection alive. I focus on what I observed, what didn’t help, and what finally made a difference.

When I write about neem, I mean NeemAzal. Unlike plain neem oil, it’s standardised (a fixed azadirachtin content), so it gives at least some guarantee that it will work.

Thrips — for a long time my toughest opponent

For a long time, thrips were the most frustrating pest I had. They’re tiny (young ones are usually pale or yellowish), hide under the leaves and love fresh, soft growth. Because of that, new leaves can unfurl already distorted before I notice anything.

What didn’t really help:

Horticultural soap or NeemAzal alone. The thrips I hit disappeared, but a few days later they were back.
Insecticide soil sticks in very airy aroid mixes. They worked slower and less reliably than spraying.

What worked better:

Spraying with flupyradifurone (Sanium System), repeated after a few days to hit the next life stages. That was the first thing that really broke the cycle.
Hard pruning on plants with lots of tiny leaflets, where covering everything with spray isn’t realistic.

Why one spray isn’t enough: female thrips lay their eggs inside the leaf tissue, and many species pupate in the substrate or in crevices of the plant. A contact spray barely reaches those stages, so the follow-up is there to hit whatever has hatched in the meantime. Flupyradifurone is systemic, meaning the plant takes it up and moves it around, so it also reaches thrips feeding where the spray didn’t land directly.

Notes from practice:

I treat twice, a few days apart, and then watch new leaves closely.
Predatory mites look great on paper, but at home they’re hard to keep going without high humidity and warmth.
I saw thrips mostly on monstera, Strelitzia nicolai, philodendrons (‘Silver Queen’, ‘Green Princess’, ‘Imperial Green’) and pothos.
I haven’t seen them on succulents, ZZ or sansevieria, but I check them anyway.

Signs of thrips feeding on a Strelitzia nicolai leaf — *Thrips love fresh Strelitzia leaves*

Philodendron Imperial Green new leaf damaged by thrips before unfurling — *New Philodendron ‘Imperial Green’ leaf partly destroyed by thrips before it even had a chance to unfurl.*

Update 2026: anthuriums and a second approach

In summer 2026 the thrips struck again. This time they did the most damage to a few Anthurium andraeanum, including my big ‘Melodia Ibis’. They had probably been there for a long time; I just didn’t know which symptoms to look for.

On these anthuriums the leaves start to sort of ripple and get thicker. Over time brown spots appear, but the tissue there doesn’t look rotten. At first I naively took the rippling for a sign of maturity, then I started to suspect macro- and micronutrient deficiencies. Only quite late did I look closely at the undersides of the leaves, and then I had no doubts left.

Rippled, thickened Anthurium andraeanum leaf damaged by thrips — *The rippling I first took for a sign of maturity.*

Underside of an anthurium leaf with pale stippling and brownish patches from thrips feeding — *The underside of the leaf: pale stippling and brownish patches. Only this made it clear what was going on.*

Of course, plenty of thrips also showed up on my Monstera deliciosa. This time I didn’t panic; I just changed my approach a bit.

I sprayed all the monsteras with Sanium System. I didn’t trust Sanium PIN sticks (according to the manufacturer, the same flupyradifurone plus nutrients) in an aroid mix, especially for my big Monstera deliciosa ‘Large Form’. Its substrate has almost no fine fraction (pumice, bark, coco chips), so I doubt the active ingredient from the sticks spreads well through it.

I repeated the spray after a week. I took the plants outside for spraying and followed safety rules: mask, gloves, the rest of the household out of the house, and our nosy beagle kept away.

The other plants got treatment depending on their shape:

Plants with a few big leaves, like self-heading philodendrons, were sprayed too.
Bushier plants that are hard to spray thoroughly, like peace lilies and aglaonemas, got Sanium PIN sticks.

I also watered the monsteras with the diluted spray solution. I’m not sure it works, since the product isn’t meant for that. I know there are products with the same active ingredient made for watering in, but the adjuvants in Sanium System might make it ineffective when applied this way.

Looking back, I can say the operation worked. This time I saved most of the plants, and the losses are small, like a leaf on one of my Monstera ‘Thai Constellation’, damaged while it was still emerging.

Monstera Thai Constellation leaf with a puckered spot and a notched, brown edge from thrips feeding — *The ‘Thai Constellation’ leaf damaged by thrips while still emerging: a puckered spot and a torn edge.*

I only got rid of my experimental monstera cuttings in semi-hydro. They sat on the windowsill, on the front line, and got badly mauled. They could probably have been saved, but they would have taken a long time to recover and looked ugly in the meantime.

I also removed one smaller anthurium, and of the ‘Melodia Ibis’ I kept only one plant. The deformed leaves made me feel the thrips could still be hiding there.

Spider mites — fine on the ficus, not on alocasias

Spider mites visit my Ficus elastica fairly regularly. Luckily, they haven’t done much damage there.

What helped:

Thorough sprays with horticultural soap or NeemAzal, mostly on the undersides. One proper session often made a big difference.
Preventive rinses with soft water and a little soap or NeemAzal.
Keeping the ficuses together and a bit away from the rest (no “leaf bridges”). It seems to slow the spread.

What I noticed on the ficuses:

I find them mostly on the undersides of the leaves, which makes early detection harder.
Early “nests” are tiny and easy to mistake for dust. Up close you can see very small, fast-moving mites in different colours (red ones too).
The webbing becomes obvious only once the infestation spreads. Before that, it’s easier to spot movement than webs.

When it gets worse:

I look for fine pale stippling on the leaves and thin webbing. I repeat the treatment every 3–5 days to hit freshly hatched mites.

Update 2026: today they’re my worst pest

Contrary to what I used to think, spider mites are now the worst pest I deal with. On Ficus elastica I could keep them under control by washing the plant with products safe for the people I live with.

On plants like alocasias this doesn’t work. The mites come back almost immediately. My guess is that with soft, juicy leaves, spraying can’t physically remove every life stage. On top of that, the fast metabolism of alocasias probably makes the problem much bigger.

As a hobbyist I don’t have access to systemic products against spider mites, and even if I did, they probably wouldn’t be safe to use at home. Spider mites are arachnids, not insects, so the flupyradifurone that works on thrips does nothing to them (more on that in Spider Mites and Alocasias: A Sad End).

Prevention with silicon supplements and Canna Cure as a natural barrier didn’t seem to help.

Biological control was still an option, but the rest of my household wasn’t thrilled about the idea, and I respect that. The alocasias stood in the living room, so in the end they had to go.

If something similar happened in my office, I’d probably bring in predatory mites. There I have more control over humidity (a humidifier), and the plants grow very close together, which raises the humidity around them on its own. At home, as I wrote in the thrips section, those conditions are hard to provide.

For now, I think the sensible prevention is to avoid plants that are especially vulnerable because of their leaf structure and metabolic rate.

I described the whole story in Spider Mites and Alocasias: A Sad End.

Aphids — easier to remove, but don’t ignore them

I most likely brought aphids in with an aglaonema. They’re rounder and slower than thrips. Under a loupe they look like tiny raindrops with legs.

What worked:

Washing the leaves and spraying with NeemAzal or horticultural soap was usually enough.
Flupyradifurone works too, if you’re already using it for thrips.

Tips:

Treat the neighbouring plants as well, and move the plant they came from away from the rest for a while.
Watch for sticky honeydew and wipe it off, so sooty mould doesn’t follow.
Repeat weekly until no new nymphs appear.

Fungus gnats — more annoying than harmful

They show up regularly and love flying into noses, mouths and tea. In my home they’re more annoying than harmful to established plants.

What helped most:

Switching to bottom watering and letting the top layer of the substrate dry out.
Yellow sticky cards, to judge the scale and catch adults.

Mixed results:

Nematodes and Bti in the watering can helped only when used correctly and repeatedly. For me, getting the watering right did more than any additive.

Yellow sticky card with trapped fungus gnats — *I'm not complaining about too many fungus gnats flying into my morning tea — but as you can see, there are still some around.*

Springtails — harmless background characters

A few times I spotted springtails in saucers, always when I had overwatered. Once I cut back on watering, they disappeared.

As far as I know, they’re harmless or even helpful detritus feeders, so I don’t treat them.

Lessons learned

Routine does the most for me: regularly checking new growth and the undersides of leaves, keeping the ficuses slightly apart, bottom watering where fungus gnats are a problem. That’s how I catch most problems early.

For aphids, and for spider mites on tough-leaved plants, soap or NeemAzal is enough. Thrips need something stronger and a follow-up, because some of their life stages sit where a spray can’t reach. Spider mites on alocasias are the one case where I lost and don’t see a good solution for a home.

I treat yellow sticky cards as a gauge: they show whether the number of fungus gnats is going up or down before I can see it with the naked eye.

Losses happen. This year it was the monstera cuttings, one anthurium, part of the ‘Melodia Ibis’ and the alocasias. Most of the collection survived both attacks, though.

If you just want something green in the office and don’t want to deal with pests, I’d pick a ZZ plant, sansevieria (now Dracaena), yucca or sturdy succulents. For me they tolerate rough handling, cope with low light better than most plants and seem to attract the usual pests less often.

In my experience two things matter. Lots of small leaves make thorough spraying hard, and soft, thin leaves with fast growth let pests multiply faster than I can wash them off. The species name tells you less than these two traits.