Mealybugs are small, soft, white insects that look like bits of cotton stuck to a plant. To get rid of them, isolate the plant, wipe each bug with rubbing alcohol, spray the whole plant with insecticidal soap, and repeat every week until no new bugs show up. This usually takes four to six weeks.
Mealybugs are slow to spread and easy to kill if you catch them early. They are hard to beat when they have had months to settle into a big plant. Start today.
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How to know it is mealybugs
Adult mealybugs are oval, soft, and covered in a white waxy fluff. They grow up to about 4 mm (1/8 in) long. Young ones are smaller and paler. They move slowly, and many sit still for days.
Look in these places first:
- Where a leaf meets the stem
- Along the underside of the leaf, near the center vein
- Inside new growth that has not opened yet
- Under the rim of the pot and on the drainage holes
You may also see small cottony tufts. Those are egg sacs. Each one holds many eggs.
Mealybugs feed on plant sap. A plant with a heavy load shows yellow leaves, stunted new growth, and leaf drop. The bugs also leave a sticky, clear residue called honeydew. A leaf that feels tacky, or a shelf under the plant that feels tacky, is a sign. Black sooty mold can grow on the honeydew.
What it might be instead
Three things get mistaken for mealybugs.
- Perlite. White bits in the soil are not bugs. Perlite does not move and does not sit on leaves.
- Powdery mildew. It is a flat, dusty film on the leaf surface. It does not have bodies you can pick off.
- Scale. Scale insects are hard brown or tan bumps that stick to stems. Mealybugs are soft and white.
If the white spot smears into a wet, pale streak when you press it with a cotton swab, it is a mealybug.
Step 1: isolate the plant
Move the plant away from every other plant right away. Mealybugs crawl from leaf to leaf when plants touch. Put the plant in a separate room if you can.
Check the plants that stood nearby. Look at the leaf joints and the undersides. Treat any plant that has bugs.
Wipe the shelf or table where the plant sat with soapy water.
Step 2: wipe off every bug you can see
Rubbing alcohol kills mealybugs on contact. Use 70% isopropyl alcohol. A bottle of 70% isopropyl alcohol from Amazon and a box of cotton swabs are all you need.
- Test first. Dab one leaf and wait 24 hours. If the leaf stays green and firm, go ahead. Some plants with thin or waxy leaves burn.
- Dip a cotton swab in the alcohol.
- Touch each bug and each egg sac. The bug will turn brown and stop moving.
- Work through the whole plant. Check the stem joints, the underside of every leaf, and the new growth.
- Throw the used swabs in the trash.
A plant with only a few bugs may be clear after one round. A bigger plant needs more steps.
Step 3: spray the whole plant
Wiping misses the tiny young bugs and the ones tucked in tight spots. A spray reaches them.
Insecticidal soap kills soft-bodied insects when it hits them. A ready-to-use insecticidal soap spray from Amazon works well. Follow the label on the bottle. Spray the tops and undersides of the leaves and the stems until the plant is wet. Do this out of direct sun, since wet leaves in strong sun can burn.
Neem oil is another choice. It smothers bugs and slows their feeding. Mix and apply it as the label says. Test on one leaf first.
Do not use dish soap you mixed yourself unless you know the exact ratio and your plant can handle it. Strong mixes strip the leaf coating.
Step 4: repeat every week
This is the step that decides whether the bugs come back. Eggs are not always killed by the first round. New bugs hatch for weeks.
Wipe and spray the plant every 5 to 7 days. Keep going for at least four weeks. Stop only after two checks in a row find no bugs. Look closely each time.
Rinsing the plant in the shower between treatments knocks off some bugs and honeydew. Use lukewarm water. Let the soil drain before the plant goes back.
Step 5: check the roots
Some mealybugs live in the soil and feed on roots. These are called root mealybugs. They are harder to spot.
Signs of root mealybugs include a plant that declines even though the leaves are clean, and white, waxy fluff on the roots or along the inside of the pot. You may see it around the drainage holes.
To check, slide the plant out of its pot. Look at the outside of the root ball.
If you find fluff, treat the roots.
- Take the plant out of the pot and shake off the old soil.
- Rinse the roots under lukewarm water until the white fluff is gone.
- Trim any roots that are black or mushy.
- Wash the pot with hot, soapy water. Throw away the old soil. Do not reuse it.
- Repot in fresh mix. Use how to repot a houseplant step by step for the full method, and read best potting soil for indoor plants for what to buy.
Water the plant lightly for a few weeks while the roots recover.
Plants that attract mealybugs
Mealybugs go after many houseplants. Jade plant, cacti, succulents, hoya, orchids, coleus, and ferns are common targets. They hide well in the tight leaf bases of succulents and in the nodes of vining plants.
If you grow these, look at them every time you water.
How to stop mealybugs from coming back
Most infestations arrive on a new plant or a plant that spent the summer outside.
- Quarantine every new plant. Keep it apart from your others for at least two to four weeks. Check the leaf joints and undersides before you move it in.
- Inspect plants before they come inside in fall. Read how to bring houseplants inside for winter without bugs.
- Look at your plants weekly. Early catches take one swab.
- Do not overfeed with nitrogen fertilizer. Soft, fast growth attracts sap feeders.
- Keep leaves clean. Dust and honeydew hide bugs.
If your plant has fine webbing and speckled leaves instead of white fluff, you have a different pest. Read how to get rid of spider mites on houseplants. If the problem is tiny flies around the soil, read how to get rid of fungus gnats in houseplants.
When to throw the plant out
A plant that is badly infested and in decline may not be worth the work. Weigh it against the risk to your other plants. If the bugs have spread to the roots and most of the leaves, cut off a clean healthy stem for a new plant, and throw out the rest in a sealed bag. Check the cutting for bugs before you root it.