Mealybugs — identification and control

How to identify mealybugs

Look for these symptoms on susceptible plants:

• White cottony tufts in leaf axils, leaf undersides, and stem joints
• Pink soft-bodied insects under the wax
• Sticky honeydew and sooty mould on lower foliage
• Yellowing and stunted growth on heavily fed plants
• White wax visible on root collar when plant is unpotted (root mealybugs)

A female lays 300-600 eggs in a cottony ovisac. Crawler-stage nymphs hatch wax-free and mobile — this is the only stage when contact sprays really work. Adults are protected by their wax coat.

Crops affected by mealybugs

Mealybugs are documented on the following host crops in authoritative extension sources. Click any crop for the full per-crop protocol, including symptoms specific to that host and the recommended biological control.

• Mealybugs on basilhigh

  White cottony tufts in the joints between basil stems and leaves; pink soft-bodied insects under the wax; sticky honeydew on lower foliage.

  Severity: High — act quickly · Year-round on indoor basil. Outbreaks typically start with one infested transplant from a supermarket or garden centre.

• Mealybugs on citrushigh

  Citrus mealybug (Planococcus citri) on leaf undersides, in twig forks, and around fruit calyxes; heavy honeydew and sooty mould on leaves below colonies.

  Severity: High — act quickly · Year-round on indoor and conservatory citrus; warmer-season outdoors. Crawlers emerge in flushes that match the host's growth.

• Mealybugs on tomatoesmoderate

  White cottony mealybug clusters in tomato leaf axils, on lower stems, and on the root collar. Honeydew, sooty mould, and stunted top growth.

  Severity: Moderate — monitor closely · Greenhouse tomatoes year-round; outdoor tomatoes during warm sheltered late summer.

• Mealybugs on strawberrieslow

  White cottony patches on strawberry crowns, leaf petioles, and at the soil line; sticky honeydew on lower leaves.

  Severity: Low — occasional · Polytunnel and protected strawberry production through the season.

Non-chemical controls

Start with the lowest-impact options before any spray. These work for the vast majority of home garden cases.

• Dab visible adults with a cotton swab dipped in 70 percent isopropyl alcohol
• Quarantine new plant arrivals for 3 weeks before mixing with your collection
• Wash leaves and stems under lukewarm water in a sink or shower
• Prune out and bin the worst-affected stems
• Unpot suspect plants and inspect roots for white waxy root mealybug colonies

Biological controls

For greenhouse, polytunnel, and indoor production, biological controls give long-term suppression without the residue or pollinator harm of synthetic sprays.

• Cryptolaemus montrouzieri (mealybug destroyer) — release larvae rather than adults for indoor use; adults disperse
• Leptomastix dactylopii — parasitoid wasp specific to citrus mealybug
• Chrysoperla carnea (green lacewing) larvae — generalist predator that eats mealybug crawlers

Organic and chemical spray options

Horticultural oil and insecticidal soap work best during the crawler stage, when nymphs have not yet built their wax shield — apply every 5-7 days to catch successive hatches. Neem oil disrupts moulting. Systemic insecticides are sometimes used in commercial nursery production but are not appropriate for edibles or indoor herbs.

How to build a mealybugs control protocol

1. Identify first. Snap a photo and confirm the species before treating — different pests respond to different protocols, and one wrong call wastes weeks. Open Growli for instant species ID.
2. Start with non-chemical control. Water blast, sticky traps, manual removal, reflective mulch, or quarantine — these alone clear roughly 60-70 percent of home cases.
3. Add biological control if you have a long-cycle crop. Greenhouse tomatoes, cucumbers, peppers, and indoor citrus all justify a single release of the right predator or parasitoid.
4. Layer in insecticidal soap or horticultural oil. Apply to thorough wetness on both leaf surfaces; repeat every 5-7 days for three weeks to catch successive hatches.
5. Reserve stronger sprays for outbreaks. Spinosad, pyrethrin, and species-specific options like Bti should be your second-line response, not your first.
6. Monitor weekly. Mealybugs populations rebound from any single intervention. Two or three weeks of follow-up checks separate a fixed problem from a recurrence.

Common mistakes

• One-and-done spraying. Mealybugs go through staggered hatches; a single spray misses everything that hatches afterwards. Always plan a 3-week protocol.
• Treating without confirming species. Insecticidal soap clears aphids but is wasted on slugs; Bti clears fungus gnat larvae but does nothing for spider mites. Wrong protocol equals wasted weeks.
• Spraying in hot sun. Soap and oil sprays burn leaves above 30 degC and on drought-stressed plants. Apply at dawn or dusk.
• Mixing biological control with broad-spectrum sprays. Pyrethroids and neonicotinoids wipe out predator releases. Use one strategy at a time, or stagger them by at least a week.

Frequently asked questions

How do I get rid of mealybugs?

Mealybugs are 3-6 mm pink soft-bodied scale insects covered in white cottony wax. They cluster in leaf joints, on stems, and on roots. Dab adults with rubbing alcohol on a cotton swab, then apply horticultural oil or insecticidal soap every 7 days for a month. Cryptolaemus montrouzieri larvae are effective for severe greenhouse infestations.

What does mealybugs damage look like?

Look for: White cottony tufts in leaf axils, leaf undersides, and stem joints; Pink soft-bodied insects under the wax; Sticky honeydew and sooty mould on lower foliage; Yellowing and stunted growth on heavily fed plants. Each host crop shows slightly different symptoms — see the per-crop pages linked above for details.

What is the best biological control for mealybugs?

Cryptolaemus montrouzieri (mealybug destroyer) — release larvae rather than adults for indoor use; adults disperse. Several other biocontrols are documented for specific conditions and host crops; see the full list above.

When during the season do mealybugs appear?

Year-round indoors and in greenhouses; warm-season outdoors. A female lays 300-600 eggs in a cottony ovisac. Crawler-stage nymphs hatch wax-free and mobile — this is the only stage when contact sprays really work. Adults are protected by their wax coat.

Are mealybugs harmful to pets and people?

Mealybugs themselves are not directly toxic to pets or people. The risk is from chemical sprays used to control them — use insecticidal soap, horticultural oil, or biological control wherever possible. Always check the product label for re-entry and harvest interval guidance, and confirm the active ingredient is currently approved via the UK HSE register or US EPA.

What plants do mealybugs not affect?

Mealybugs most commonly affect basil, citrus, tomatoes, strawberries. Plants with thick, waxy, or hairy foliage typically resist this pest better than soft-leafed crops. For pet-safe houseplant alternatives that resist most common pests, see our pet-safe houseplants guide.

Can I use the same protocol indoors and outdoors?

The biological-control choices change (indoor releases of ladybirds rarely work; predatory mites and parasitoid wasps do), but the spray protocols (insecticidal soap, horticultural oil, neem) translate directly. Outdoor cases benefit from reflective mulches and companion planting; indoor cases benefit from quarantine and routine wipe-downs.

Sources

Identification and control guidance sourced from US Cooperative Extension publications (UC IPM, NC State, UMD, UMN, Penn State, CSU, UF/IFAS EDIS), Clemson HGIC fact sheets, Royal Horticultural Society guidance, and Cornell NYS IPM Biocontrol fact sheets. Reviewed by the Growli editorial team in May 2026.

Keep going

• Mealybugs — full kill protocol (article)
• All 8 garden pests covered in this guide
• Garden pest identification — complete article
• Companion planting chart (pest-deterrent pairings)
• Common houseplant diseases