The Ultimate Guide to Indoor Plant Pests & Bugs

Bad bugs: spider mites

Spider mites are probably the most common houseplant pest, and easily the most frustrating. They aren't insects but arachnids, related to spiders and ticks. They're tiny, usually under a millimetre, which is why most people don't spot them until the population has already exploded. Up close they look like specks of dust that move: red, brown, yellow or near-translucent, usually huddled on the undersides of leaves where they're harder to see and harder to reach with a spray.

They feed by piercing individual leaf cells and draining them. The result is a pale, dusty stippling across the leaf surface. As more cells die, leaves yellow, take on a bronze or silvery tinge and eventually go crisp and drop. The clearest sign of a serious infestation is fine silk webbing, usually around new growth, in the joints between leaf and stem, or strung between leaves. The life cycle is what makes them so awful. In warm, dry conditions a female can lay hundreds of eggs that hatch into reproducing adults in about a week. Catch them early or you'll be chasing them for months.

Time of year when most prominent

They can show up any time of year indoors but boom in warm, dry, still air. In a UK home that means winter, when central heating dries the air to desert levels, and any summer heatwave that bakes south-facing windowsills. Plants near radiators, in direct hot sun, or in a still corner with no airflow are usually the first to go.

How to treat and prevent

One-off treatments rarely work because the eggs survive most sprays. You need a few rounds.

1. Isolate and clean: Move the affected plant away from the rest of your collection straight away. Put it in the shower or take it outside and rinse it thoroughly to physically wash off as many mites and webs as you can. For more delicate plants, wipe every leaf and stem (top and bottom) with a damp cloth. It's tedious, but it cuts the population dramatically before you spray.

2. Apply targeted treatments: After cleaning, you need something to kill what's left.

• Insecticidal soaps and oils: These work by suffocating mites on contact rather than poisoning them, so they're safe enough indoors. Neem oil also disrupts growth and acts as a repellent. Our Natural Pest Control Spray is ready to use; alternatively, mix Pure Neem Oil with water and a drop of washing-up liquid to emulsify it. Spray everything, including leaf undersides, until the plant is dripping.
• Biological control: For a longer-term fix, introduce a predator. The most useful one against spider mites is another mite, Amblyseius californicus, which thrives in the same warm, dry conditions. Hang the slow-release sachets on the plant and they keep working for weeks.

3. Be persistent: Most treatments don't kill the eggs. Repeat every 5 to 7 days for at least three or four weeks so you catch each new wave before they can breed.

4. Prevention: Make the conditions hostile to them. Inspect regularly, especially under leaves. Bump up humidity by grouping plants, running a humidifier, or sitting pots on pebble trays. A well-watered, well-fed plant is more resilient than a stressed one. Quarantine any new plant for at least a month before it joins the others.

Q&A

Q: Are spider mites harmful to humans or pets?

A: No. They feed on plants, full stop. They won't bite you, infest your carpet, or bother your cat.

Q: I treated my plant, but the spider mites came back. What did I do wrong?

A: Almost certainly the eggs. A single treatment kills the active mites but leaves the next generation untouched, and they'll hatch a few days later. You need repeated applications every 5 to 7 days for several weeks to break the cycle properly.

Q: Why do my Calatheas, Alocasias, and palms seem to get spider mites so often?

A: Thin-leaved tropicals like Calatheas, Marantas, Alocasias and Kentia palms are easier for mites to pierce. They also want more humidity than most UK homes provide, so they're already a bit stressed, which makes them an easier target. The RHS lists more than 180 plant species that can be affected, but these tropicals are the usual suspects.

Q: Can I really get rid of them for good?

A: Yes. It comes down to persistence (repeated treatments), thoroughness (every surface, especially undersides), and changing the environment so it's less hospitable, which usually means more humidity and better airflow. Once they're gone, regular checks keep them gone.

Bad bugs: mealybugs

Mealybugs look like small bits of cotton wool tucked into the joints and crevices of a plant. They're sap-sucking insects, and the white fluff is a waxy coating the females secrete to protect themselves and their eggs. That coating is also why a lot of contact sprays bounce off them. They're oval, segmented, slow-moving, and they like sheltered spots: leaf nodes, the central vein, and unfurling new growth. Some species attack the roots instead, and those root mealybugs are much harder to spot until you tip the plant out of its pot.

The damage works in two ways. Like most sap-suckers, they drain nutrients and moisture, which leads to yellowing leaves, leaf drop, stunted growth and a generally tired-looking plant. A heavy infestation can kill it. The second issue is what they leave behind. As they feed, mealybugs excrete a sticky, sugary liquid called honeydew, which coats the leaves, drips onto the floor, and makes everything tacky. Honeydew then breeds sooty mould, the black powdery coating you sometimes see on leaves. The mould doesn't feed on the plant directly, but it blocks light and slows photosynthesis, which doesn't help an already weakened plant.

Time of year when most prominent

Indoors, mealybugs don't really have a season. The conditions of a UK home (warm, fairly humid, never freezing) suit them year-round. They tend to ramp up when plants are putting on lush new growth in spring and summer, because the soft tissue is easier to feed on. Over-fertilising encourages exactly that kind of soft growth, which makes the problem worse, and over-watering creates the muggy microclimate around the base that they enjoy. Whether you get them tends to depend more on how you're caring for the plant than on what month it is.

How to treat and prevent

Their wax armour and habit of hiding in tight spots means a single spray almost never finishes them off.

1. Isolate and remove by hand: Move the plant away from the rest of your collection. Because mealybugs are slow and largely stationary, manual removal is genuinely effective. Dip a cotton bud, soft cloth or small paintbrush in rubbing (isopropyl) alcohol and dab it directly onto each visible mealybug and egg sac. The alcohol dissolves the waxy coating and kills them on contact. Check every leaf axil and crevice. For really heavy infestations, prune off the worst-affected stems.

2. Wash and spray: Rinse the plant under a tap or shower to wash away honeydew, sooty mould and any tiny mobile crawlers. Then spray.

• Horticultural oils and soaps: You want something that can get through the wax. Pure Neem Oil is a solid organic choice; it disrupts their growth cycle and acts as a repellent. Spray until it's dripping off the leaves, and pay special attention to undersides and stems.
• Biological control: The best mealybug predator by some distance is a small ladybird beetle from Australia, Cryptolaemus montrouzieri, known as the Mealybug Destroyer. The larvae in particular eat mealybugs at every life stage and will keep working for weeks.

3. Repeat and watch: Reapply every 7 to 10 days for several weeks while new crawlers hatch out of protected egg sacs. Keep checking the plant for fresh white fluff in the weeks after.

4. Prevention: Inspect every new plant before it comes through your door, including the undersides and dense growth. Don't over-water or over-fertilise: soft, sappy growth is what mealybugs love. Decent airflow helps too.

Q&A

Q: Where did the mealybugs on my plant come from?

A: Usually the plant arrived with them. Nurseries and shops aren't immune. They can also come in on contaminated potting compost, garden tools, or cut flowers. In summer they sometimes wander in through an open window from outdoor plants.

Q: I found white fluff in the soil of my plant. Is this also mealybugs?

A: Maybe. It's also commonly a harmless saprophytic fungus that grows on decaying organic matter in the compost. The way to tell: tip the plant out and look at the roots. If you see small, white, waxy insects clustered on the roots, those are root mealybugs and they need a different treatment, usually a soil drench or a complete repot with a root wash.

Q: Is the sticky residue on the shelf below my plant caused by the mealybugs?

A: Yes, almost certainly. That's honeydew, the sugary waste they excrete. Wipe it off with soapy water before sooty mould moves in or ants find it.

Q: I used rubbing alcohol, but some of my plant's leaves look damaged. Why?

A: Rubbing alcohol can scorch delicate leaves like ferns and Calatheas. Test it on one leaf and wait 24 hours before treating the whole plant. Diluting it 50:50 with water reduces the risk of burn while still working on the bugs.

Bad bugs: aphids

Most people know aphids as greenfly or blackfly. They're small, soft-bodied, pear-shaped, and they come in green, black, yellow, white, or even pink depending on the species and what they're eating. You'll usually find them in tight clusters on the softest bits of the plant: new shoots, flower buds, and the undersides of young leaves. The reason they're such a nightmare indoors is how fast they breed. In a warm home, females reproduce without needing a mate and give birth to live young, so a handful of aphids can become a serious infestation in a couple of weeks.

The damage is twofold. First, the feeding itself: they punch into the plant's phloem and drain sap, which leads to yellowing leaves, curled or misshapen growth, and an overall wilted look. Second, the sticky residue. Like mealybugs, aphids excrete honeydew, and that honeydew quickly grows sooty mould, the black powdery film that blocks light from the leaves. Honeydew also attracts ants, which will then "farm" the aphids for the sugar and protect them from predators, which is its own special little headache.

Time of year when most prominent

For houseplants, aphids are a year-round problem rather than a seasonal one. The cold doesn't kill them off the way it does in the garden, so they just keep going. Population spikes tend to follow growth spikes, which means spring and summer when plants are pushing out tender new shoots. Heavy nitrogen feeding makes things worse: it produces exactly the soft, sappy growth they prefer. If you start seeing winged aphids, the colony is overcrowded and trying to spread to nearby plants, which is when you really need to act.

How to treat and prevent

Move quickly and use more than one method.

1. Isolate and remove physically: The moment you spot them, separate the plant from the rest. For light infestations, you can wipe colonies off with your fingers, a damp cloth, or a soft brush. For larger ones, take the plant to the sink and blast the aphids off with a strong jet of water. For fragile plants, invert the pot and dunk the foliage in a bucket of room-temperature water. Heavily infested stems can just be pruned off and binned (not composted, which spreads the problem).

2. Apply targeted treatments: After knocking the numbers down physically, follow up with a spray.

• Soapy water or insecticidal soap: A few drops of mild washing-up liquid in water still works. It dissolves the aphid's outer layer and dehydrates them. Spray everything thoroughly, including leaf undersides. A pre-mixed insecticidal soap is more reliable if you don't want to fiddle with ratios.
• Neem oil: Pure Neem Oil works as a repellent, anti-feedant and growth disruptor in one. Dilute and apply per the instructions, and stay consistent.
• Biological control: Ladybirds, especially the larvae, eat aphids voraciously. You can buy them and release them onto affected plants. Parasitic wasps from our AphiScout mix are another option: they lay eggs inside aphids and the larvae eat them from the inside out, which is grim but extremely effective.

3. Stay consistent: One treatment is rarely enough. Reapply every few days for a couple of weeks to catch the next generation as they hatch.

4. Prevention: Check every new plant carefully before bringing it home. Wipe leaves now and then, remove dead foliage, and don't over-feed. A healthy plant is a less appealing one.

Q&A

Q: I've sprayed my plant with soapy water, but the aphids are still there. Why didn't it work?

A: Soapy water is a contact treatment: it only kills what it actually touches. Anything hiding in a crevice or under a leaf survives, and there's no residue to catch the next batch. Repeated, thorough applications every few days are the only way to stay ahead of them.

Q: How can I get rid of aphids for good?

A: Combine physical removal, repeated treatments with something like neem oil, and good preventative care. If you want a longer-term fix, beneficial insects (ladybirds, lacewing larvae, parasitic wasps) are arguably the most reliable, because they keep working without you having to remember.

Q: My plant's leaves are sticky. Is this definitely aphids?

A: Sticky leaves mean honeydew, which several sap-suckers produce, including aphids, mealybugs and scale. It's a strong signal but not proof. Look closely at the new growth for the small pear-shaped insects to be sure.

Q: Are the chemicals in aphid sprays harmful to my pets?

A: For houseplants, start with the least toxic options: water sprays, insecticidal soaps, and organic oils like neem. These are generally safe around pets when used as directed. Save chemical pesticides for last resort, keep pets out of the room until everything is dry, and read the label.

Bad bugs: thrips

Thrips are small, slim, fast and very good at hiding, which is why they often do real damage before anyone notices them. Adults are usually one or two millimetres long, yellowish brown to black, with two pairs of narrow fringed wings (the order name Thysanoptera literally means "fringed wings"). They avoid light, so they tend to be on leaf undersides, tucked into folds of new growth, or deep inside flower buds. The life cycle includes two non-feeding pupal stages that often happen in the soil or leaf litter, which is why foliar sprays alone never quite finish them off.

Their feeding method is unusual. Rather than piercing and sucking, they rasp the surface cells of leaves and flowers and lap up what comes out. The damage looks silvery or pale and stippled, and is sometimes mistaken for spider mite damage. The giveaway is the tiny black specks dotted across the silver patches: that's thrips frass (their droppings). On new growth, the damage is worse, because they get inside the rolled leaf before it opens, so the leaf emerges scarred, deformed and sometimes torn. Flower buds may turn brown and never open. Thrips also spread plant viruses between hosts, which adds another reason to take them seriously.

Time of year when most prominent

Indoors they're a year-round problem, but they pick up speed in spring and summer when plants are growing fast and producing the soft new foliage they prefer. They turn up on new plants, hidden in cut flowers, or simply fly in through an open window on a warm day. Monsteras, Hoyas, Philodendrons and Fiddle Leaf Figs are especially prone, possibly because the developing leaves stay rolled up long enough for thrips to make themselves at home.

How to treat and prevent

You need to hit them on the plant and in the soil. Just spraying the leaves never works on its own.

1. Isolate and clean thoroughly: Separate the affected plant immediately. Give it a robust shower to dislodge as many thrips as possible, then wipe each leaf top and bottom with a damp cloth to remove the rest along with the frass.

2. Use more than one method: Their life cycle means a single approach almost never finishes them off.

• Foliar sprays: An insecticidal soap or horticultural oil smothers larvae and adults on contact. Our Natural Pest Control Spray works well here. For a more residual organic option, a Pure Neem Oil solution disrupts feeding and growth. Spray everywhere, every few days, for several weeks.
• Sticky traps: Thrips are drawn to certain colours. Blue or yellow sticky traps near the plant catch flying adults and give you a sense of how bad the infestation is. Blue tends to outperform yellow specifically for thrips.
• Biological control: The most effective long-term answer is the predatory mite Amblyseius cucumeris, which hunts thrips larvae on the leaves. Slow-release sachets put a breeding colony on the plant for several weeks. There's more on these in our guide to good bugs.

3. Break the soil stage: Soil drenches exist, but for indoor plants a less chemical option is to repot into fresh, sterile compost after washing the roots. That gets rid of any pupae lurking in the old mix.

4. Prevention: Quarantine new plants for at least four weeks. Check cut flowers before they come in. Keep airflow up and don't let plants get too stressed.

Q&A

Q: Why are the new leaves on my Monstera emerging damaged and full of holes before they even unfurl?

A: Classic thrips. They crawl into the rolled-up leaf and feed on the soft tissue inside. As the leaf unfurls, the early damage stretches out into tears, distortion and silvery scars. If you see this, check the plant for thrips straight away.

Q: I've sprayed my plant multiple times, but I keep seeing more thrips. What am I doing wrong?

A: Almost always the soil-dwelling pupae. Foliar sprays don't reach them, so new adults keep emerging into a freshly cleaned plant. You need persistent spraying combined with something that hits the larvae or the soil stage, like Amblyseius cucumeris.

Q: Are thrips harmful to people or pets?

A: No. They very occasionally bite humans and cause a small, brief skin irritation, but it's rare and not medically significant. They're an annoyance, not a danger.

Q: I can't see any bugs, but my leaves have silvery patches and black dots. Could it still be thrips?

A: Yes. The silver-plus-black-dots combination is a strong thrips signature even when you can't see the insects, since they're very good at hiding. The RHS lists this damage pattern as one of the main ways to diagnose them. Hold a piece of white paper under an affected leaf and tap it; you'll usually shake a few onto the paper.

Bad bugs: fungus gnats

Fungus gnats (also called sciarid flies) are the small dark flies you see flitting around the base of houseplants and bumping into nearby windows. They're often confused with fruit flies, but they're a different insect entirely, and they live in plant compost rather than around fruit. The good news: they don't really damage healthy mature plants. The bad news: they're annoying, and their presence usually means your soil is staying too wet.

The whole life cycle revolves around the compost. Adults don't feed on the plant; they exist to mate and lay eggs. A female lays up to 200 eggs in the top layer of damp organic-rich compost, and these hatch within a few days into translucent maggot-like larvae with a small black head. The larvae live in the top inch or two of soil, eating fungi, algae and decaying matter. They only really chew plant roots in heavy infestations, and even then it's mostly seedlings and cuttings at risk. After a couple of weeks of feeding, they pupate in the soil and emerge as the next generation. The whole cycle can complete in three to four weeks in warm conditions.

Time of year when most prominent

Fungus gnats don't follow seasons; they follow watering habits. An infestation almost always means the compost is staying too wet, whether that's from a heavy hand on the watering can, pots without drainage, or a dense potting mix. They can be especially noticeable in autumn and winter, when lower light and cooler temperatures slow plant growth and the soil takes ages to dry out. Peat-free mixes, which often contain composted bark and coir, can also support more of the fungal growth that the larvae feed on.

How to treat and prevent

Two-part attack: deal with the flying adults, and deal with the larvae in the compost.

1. Sort the watering (the most important step): Fungus gnat larvae can't survive in dry conditions. Let the top one to two inches of compost dry out completely between waterings. For most houseplants this is healthier anyway. Bottom-watering helps too: sit the pot in a saucer of water for 30 to 60 minutes so the roots draw water up while the surface stays dry and uninviting for egg-laying adults.

2. Trap the adults: While the soil is drying, deal with the flies. Yellow sticky traps work brilliantly. Adults are drawn to yellow and stick to the surface for good. Push the traps into the compost on stakes or lay them flat on the rim of the pot. They also give you a useful read on how bad the infestation is. Our Yellow Sticky Traps are designed for exactly this.

3. Kill the larvae in the soil:

• Biological control: The cleanest fix is to water in a beneficial nematode, Steinernema feltiae. These are microscopic worms that hunt and kill fungus gnat larvae from the inside. They're harmless to plants, pets and people but devastating to the gnat population. Our No Gnat Powder is the easiest way to apply them.
• Physical barriers: Once the worst is over, top-dress the compost with about an inch of decorative sand, fine horticultural grit or clay granules. Adults can't get through to lay eggs.

4. Prevention: Check new plants before they come home. Bagged compost can sometimes carry larvae too, so seal any unused bag. The single biggest preventative measure remains the obvious one: don't over-water.

Q&A

Q: Are fungus gnats the same as fruit flies? They look similar.

A: No. Fungus gnats are slimmer, blacker and more delicate, like a tiny mosquito, and they live around plant pots. Fruit flies are stockier, often brownish with red eyes, and they swarm around fermenting fruit, bins and drains.

Q: Will these gnats actually kill my big, established Monstera?

A: Almost certainly not. For a mature, healthy houseplant, fungus gnats are a cosmetic problem and an annoyance. The larvae feed on fungi and decaying matter, not on robust roots. The only real risk is to seedlings and delicate cuttings, where heavy larval populations can damage the developing roots.

Q: I've been letting my soil dry out, but the flies are still here. What now?

A: Drying the soil is the most important step, but adults can live for about a week and they'll have already laid eggs before the soil started to dry. Combine the dry-out approach with yellow sticky traps for the adults and a nematode treatment for the larvae already in the compost. That covers all three life stages.

Q: Are nematodes safe to use in a home with children and pets?

A: Yes. Steinernema feltiae is a naturally occurring microscopic organism that targets specific insect larvae and nothing else. They're harmless to humans, pets and plants. The RHS rates them as one of the safest indoor biological controls.

Bad bugs: scale

Scale insects don't really look like insects. They look like small, immobile, barnacle-like bumps stuck to the stems, leaf joints and undersides of leaves, often along the central vein. The most common type on houseplants is brown soft scale: a waxy, slightly domed brown or tan shell about 2 to 5mm across. What you're looking at is the adult female, which has lost her legs and antennae after settling on a feeding spot. She lives under that protective shell, sucking sap and laying eggs underneath herself. The disguise is so good that a lot of people mistake them for natural bumps in the woody stem until the infestation is well advanced.

The damage is slow but it adds up. Like other sap-suckers, scale insects tap the plant's vascular system and drain it of sap. Light infestations rarely show much, but as numbers grow you'll see yellowing leaves, slow or weak growth, and premature leaf drop. The other obvious sign is honeydew: a clear, sticky liquid the insects excrete that coats leaves, stems and whatever's beneath the plant. Honeydew then breeds black sooty mould, which doesn't directly damage the plant but does block light from the leaves, slowing photosynthesis and adding to the stress.

Time of year when most prominent

Scale is a year-round problem indoors. UK home conditions are stable enough that they reproduce continuously, without the seasonal pauses they'd hit in the garden. Most infestations come in on a new plant from a nursery or shop. They particularly like woody-stemmed plants such as Ficus (including the Fiddle Leaf Fig), Citrus, Hoyas, and some ferns and palms. You'll often notice them spreading more in spring and summer when the plant is growing and there's more sap to feed on.

How to treat and prevent

Their armour means simple sprays often bounce off. You need to get hands-on.

1. Isolate and remove by hand: As soon as you spot scale, separate the plant from the rest. Adults can be scraped off with a fingernail, a cocktail stick, or a cotton bud dipped in rubbing alcohol (which dissolves the waxy shield). Be firm but careful and try to get every bump. It's slow work, but it's the single most effective thing you can do.

2. Wash the foliage: Once the scale is off, the plant will still be coated in sticky honeydew and possibly sooty mould. Wipe everything down with a damp cloth or give the plant a gentle shower. This also removes any stray crawlers.

3. Treat to kill the crawlers: The adults may be gone, but the eggs and the tiny mobile juvenile "crawlers" hidden under the old shells are still there. Crawlers are the only mobile stage and the most vulnerable.

• Horticultural oils and soaps: A horticultural oil or insecticidal soap smothers the crawlers. Pure Neem Oil mixed with water and a drop of soap suffocates them and acts as a deterrent. Spray everything, especially stems and leaf undersides. Our Natural Pest Control Spray is a ready-to-use option.

4. Be persistent: Repeat the spray every 7 to 10 days for at least a month so you catch each wave of crawlers as they hatch. Keep checking the plant weekly for new bumps.

5. Prevention: Check every new plant carefully, paying attention to stems and leaf joints. Quarantine for a few weeks. A healthy plant that's properly watered and fed is harder to overwhelm.

Q&A

Q: Are these strange brown bumps on my Ficus tree part of the plant?

A: They're not. Scale is good at blending in. Try gently scraping one with your fingernail. If it pops off, it's a scale insect. A natural part of the stem won't.

Q: I've scraped off all the scale I can see, but my plant is still sticky. Why?

A: That's leftover honeydew. It hangs around until you wash it off, even after the bugs are gone. Wipe leaves and stems down with mild soapy water; that also stops sooty mould getting going.

Q: Why did my scale infestation return after I thought I had removed them all?

A: Almost always because the crawler stage was missed. You got the static adults but their offspring hatched out and set up new feeding spots. That's why follow-up sprays with horticultural oil are so important: they target the vulnerable young stage you can't see.

Q: What is the 'crawler' stage? I can't see anything moving.

A: Crawlers are the juvenile stage of a scale insect. They're tiny, often translucent or yellowish, and look like a speck of dust. They hatch from eggs hidden under the mother's shell and crawl out to find their own feeding spot. According to Clemson Cooperative Extension, this is the most vulnerable stage and the main target for sprays. Because you can't really see them, you have to assume they're there and treat the plant even after manual removal.

Good bugs: ladybirds

Now to the good guys, starting with the most familiar one. Ladybirds (family Coccinellidae) are mobile, hungry pest controllers, and their reputation is deserved. Releasing them onto an infested plant is one of the most effective and least chemical things you can do.

Most people picture the adult: a small, domed, red or orange beetle with black spots. The larva looks completely different, and people often mistake it for a pest. It's elongated, segmented, alligator-like, dark grey or black with orange or yellow markings, wingless, and constantly on the move. A single larva can eat hundreds of aphids before it pupates. Adults eat pests too, but the larval stage is where the real damage is done.

Target pests and how they work

Ladybirds will eat various soft-bodied pests, but their clear preference is aphids (greenfly and blackfly). Both adults and larvae work through aphid colonies fast, especially the soft tissue on new growth. They've been used as a biological control in agriculture for over a century for a reason.

If aphids run short, they'll happily eat:

• Spider mites
• Mealybugs
• Scale insect crawlers (the vulnerable juvenile stage)
• Thrips
• Whiteflies
• The eggs of various insects

The method is simple: hunt, capture, eat. You're releasing a small, targeted hunting party that works through the population while you do other things.

How to introduce and encourage them

You can't just open a tub of ladybirds in the middle of a room and hope.

1. Order from a reputable source: A specialist supplier sends healthy native species (typically two-spot or seven-spot ladybirds) ready to work. Random garden ladybirds are a bit of a lottery.

2. Release at the right time: Evenings or cool, overcast days are best. They're less likely to fly straight at the brightest window. Lightly mist the leaves of the affected plant beforehand: the ladybirds will be thirsty and drink before going looking for food.

3. Put them on the problem: Place or shake the ladybirds directly onto the affected leaves. Right next to the food, they're more likely to settle and start laying eggs.

4. Stop spraying: Insecticides, including organic ones like neem oil, will kill your ladybirds along with the pests. Stop all sprays at least a week before release and don't resume on plants where the ladybirds are working.

5. Pick the right space: Ladybirds work best in contained spaces like a conservatory, greenhouse or grow tent, where they can't easily wander off. In an open-plan room, expect some to leave. Plenty will stay if there's food.

Q&A

Q: I released ladybirds in my living room. Will they just fly away?

A: Some adults will, especially towards bright lights and windows. Releasing them in the evening directly onto an aphid-infested plant gives them the best reason to stay. The larvae, which are wingless and the more useful predators anyway, can't leave until they pupate. If the adults stay long enough to lay eggs, you'll have a new wave of larvae working for you.

Q: I found a strange looking black and orange bug on my plant. Is it a pest?

A: Probably not, especially if it looks like a tiny spiky alligator with orange spots. That's a ladybird larva, and it's the best thing currently on your plant. Leave it alone.

Q: Is it better to release adult ladybirds or the larvae?

A: Both have their merits. Adults cover more ground and lay eggs, but they can also fly off. Larvae are more reliable for a targeted job because they can't leave the plant and they eat constantly. Many suppliers, ourselves included, sell mixes or let you choose.

Q: Can I just collect ladybirds from my garden and bring them inside?

A: You can, but it's a gamble. Wild-caught ladybirds may carry parasites or diseases, and you might accidentally bring in the invasive Harlequin ladybird, which out-competes native species. Buying from a reputable source is the safer route.