You've spotted little tufts of white cotton wool in the leaf joints of a favourite plant, and a quick search has you fearing the worst. Take a breath: mealybug is one of the most common houseplant pests in the world, it moves slowly, and it is very treatable. Finding it is not a sign you've done anything wrong.
How do I know it's mealybug?
Look for white, cottony fluff in the places plants are hardest to clean — leaf axils (where leaf meets stem), the undersides of leaves, and around new growth. The bugs themselves are small, oval and powdery-white, and they barely move. You may also notice sticky, shiny patches on leaves or the surface below the plant — that's honeydew, which they excrete — sometimes followed by a black sooty mould growing on it.
How common is mealybug — and how did it get in?
Extremely common — alongside spider mite, it's the pest we're asked about most. Mealybugs hitchhike: on a new plant, in compost, occasionally through an open window in summer. Eggs can sit dormant and hatch weeks after a plant arrives looking spotless, which is why even immaculate collections get them. Every nursery, botanical garden and plant shop on earth deals with mealybug; it is part of keeping plants, not a verdict on your care.
How serious is it?
Caught at the white-fluff stage, not very. Mealybugs weaken a plant slowly by sucking sap — you have weeks to act, not hours. A healthy, established plant will sail through an infestation that's dealt with. The real risk is ignoring it, because they multiply steadily and spread to neighbouring plants.
How do you get rid of mealybugs?
Four steps. One: move the affected plant away from its neighbours, and give those neighbours a close inspection. Two: physically remove what you can see — a cotton bud dipped in rubbing alcohol dissolves the waxy coating and kills them on contact; for a bigger plant, a firm shower with the spray head does a lot of the work. Three: spray thoroughly with SB Plant Invigorator — our treatment of choice — covering stems, leaf joints and the undersides of every leaf until dripping. Four: repeat weekly for three to four weeks, so you catch the generations that hatch after each spray. Stop when you've had two consecutive clean weeks.
Why SB Plant Invigorator?
It's what we use in our own nursery. SB works physically rather than chemically — a soap-like wetting agent that blocks the insect's breathing pores — which means pests can't build resistance to it, it's safe to use indoors, and it doubles as a foliar feed, so the plant is being fed while it recovers. It works on greenfly, whitefly and spider mite too, so the same bottle covers essentially every common houseplant pest. Because it kills on contact rather than lingering, coverage is everything: spray like you're washing the plant, not perfuming it.
What about a heavy infestation?
If a stem or leaf is thick with them, prune it off and bin it (not the compost heap), then treat what remains. Check the pot rim, the underside of the pot and the top layer of compost — root mealybug and strays hide there. For a plant that's more bug than leaf, weigh up whether it's worth the campaign; sometimes a fresh start protects the rest of your collection.
How do I stop it coming back?
Inspect new plants when they arrive and keep them apart from the collection for a week or so if you can. Glance into leaf joints when you water — thirty seconds a week catches an outbreak while it's still a cotton bud job. And if you're ever unsure what you're looking at, send us a photo — every Plant Drop plant comes with lifetime horticultural advice, and identifying pests is exactly what it's for.
