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Mealybugs

Pest

Mealybugs are small, soft bodied insects that feed on plant sap by piercing the surface of leaves and stems. They can weaken plants significantly and leave behind sticky residue that encourages mold growth.

Symptoms by part

Leaves

You will see white, cottony masses tucked into the undersides of leaves or along the veins, often accompanied by a sticky substance called honeydew.

Stems

Look for clusters of white, fuzzy insects hiding in the crevices where leaves meet the stem or along the main growth points.

Causes

  • Overcrowded plants with poor air circulation.
  • Bringing home new, infested plants without checking them first.
  • Excessive nitrogen fertilizer which creates soft, succulent growth that attracts pests.
  • Warm, dry indoor environments that lack natural predators.

Could be confused with

  • Cottony Cushion Scale · This pest produces a rigid, fluted white egg sac that is much firmer and more structured than the soft, fluffy mass of a mealybug.
  • Powdery Mildew · This is a fungal disease that looks like a dusting of white flour on the leaf surface, whereas mealybugs are distinct, individual insects.

Treatment

  1. Isolate the infested plant immediately to keep the bugs from moving to your other plants.
  2. Use a cotton swab dipped in rubbing alcohol to touch and kill individual mealybugs on the leaves and stems.
  3. Gently wash the entire plant with a soft cloth and mild soapy water to remove the white cottony masses and sticky honeydew.
  4. Prune away heavily infested stems or leaves that are too crowded to clean thoroughly.
  5. Apply a spray containing fatty acids to the entire plant surface, ensuring you reach the undersides of leaves and stem joints, follow the label.

Without chemicals

  • Isolate the plant in a separate room.
  • Prune away severely infested parts to reduce the population.
  • Use a strong stream of water to dislodge insects from sturdy plants.
  • Wipe down leaves and stems with a damp cloth.

Chemical options

  • Fatty acids, spray directly onto the insects to disrupt their outer layer, follow the label.

Preventing it

  • Inspect all new plants carefully for white fuzzy spots before bringing them into your home.
  • Keep plants spaced out to ensure good airflow.
  • Avoid over fertilizing with high nitrogen products.
  • Wipe down plant leaves regularly to keep them clean and dust free.

Season

They are most active during the warm growing season, though they can persist year round in indoor environments.

Spread risk

High

Severity

Moderate

When to act

Act as soon as you spot the first white, cottony mass to prevent a full scale infestation. If the plant is severely stunted or the infestation covers the entire structure, it is often better to discard the plant to protect your collection.

Think it's Mealybugs?

This guide covers the general picture. Pocket Botanist looks at your actual plant from a photo and tells you what's really going on, how serious it is, and what to try first. Identification and a health check are free.

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Questions people ask

Can I just wash the mealybugs off with water?
Washing helps reduce the numbers, but it rarely removes every single egg or hidden nymph, so you will likely need to follow up with alcohol or a fatty acid spray.
Why do my plants get sticky when they have mealybugs?
The stickiness is honeydew, which is a sugary waste product excreted by the mealybugs as they feed on the plant sap.
Will mealybugs kill my plant?
If left untreated, a heavy infestation will drain the plant of nutrients, causing leaves to yellow, drop, and eventually leading to the death of the plant.

Plants it affects

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This guide was generated with AI and is general information, not horticultural advice. Read about how we build these guides.