Plant Pest - Mealybug

Common Name: Mealybug
Scientific Name: Planococcus citri, Pseudococcus longispinus, P. calceolariae and others

Mealybug is a small,  sap-sucking insect which secretes a powdery wax substance to protect itself. When Mealybugs appear on leaves and stems, they are easily identifiable by their white cottony coating. Mealybugs thrive in warm humid conditions and are commonly found on houseplants and in greenhouses.

Mealybugs cause damage by sucking sap from their host plants, and they have a tendency to favor new growth, as do many pests, and may sometimes be accompanied by ants which ‘farm’ them for their honeydew. The leaves become yellowed and eventually fall off the plant as a result of their damage. Moreover, they can cause fruits, vegetables, and flower buds to drop prematurely. In severe infestations, their honeydew (waxy excretions) can stimulate the growth of Black Sooty mould.

Mealybug Pest Identification

• Leaves fluffy white residue - looks like tiny fluffy cotton wool on your plants.
• Soft bodied and slightly pink with white covering.
• Black sooty mould - sign they may be present.
• Plant looks unhappy or weakened.
• Waxy white residue on roots.

How do Mealbug spread?

• Mealy bugs are everywhere and often hitch a ride on other plants.
• Can hitch a ride  your clothing from outdoors or other infested spaces.
• They are slow movers and can only move during their nyphm (young) phase in their life cycle.
• Males can fly during their reproductive stage, and will fly in from open windows.

What Part of the Plant  can Mealybug be found?

• Usually in clusters under leaf axils, sheaths, in twining stems or under loose bark.
• Some species are found on roots as a white fluffy residue.
• Often found attacking new growth or under leaves as they are sap suckers.

Conditions the enhance or hinder the proliferation of Mealybugs?

Enhance: 

• Warm conditions 25°C and above.
• High humidity.
• Plants high in nitrogen and have soft leafy growth, eg: Tropicals, though they can be found on Succulents kept in Humid conditions.

Hinder: 

• Cooler Conditions of 20°C and lower.
• Lower humidity levels of 50% and less.

Mealybug Pest Treatment Plans

Small manageable infestations

• Quarantine your infected plant.
• Wash off Mealybug with a strong jet of water.
• Use rubbing alcohol (Eg: Surgical Spirits) - dip a cotton swab in alcohol and use to remove mealybug.
• Homemade pesticide: 2 x Garlic clove, 1 tsp cayenne pepper powder or 1 x chilli, blend together in 1 liter warm water and allow to steep for 1 hour. Strain and place into a Spray Bottle with 2 drops of dish soap. Spritz plant thoroughly.
  
• Allow to dry, and wipe down with paper towel to remove dead mealybugs.

For tips on homemade pesticides check out: 8 Homemade Pesticide Sprays for indoor plants.

Large infestations

• Quarantine your infected plant .
• Remove any highly infested foliage and stems.
• Rinse off leaves to remove pests.
• Spray with an organic pesticide such as Neudosan or Pyrol.
• Treat every 7 - 10 days until infestation has disappeared.

Mealybug Preventative Measures

• Choosing plants that are less susceptible.
• Removing hiding spaces, such as debris (fallen leaves etc) from planter.
• Feed and water less often as this produces harder growth and less nitrogen production in plants.
• Inspect new plants and keep quarantined for a month.
• Keep ant populations under control indoors as they transport babies and protect adults.
• Keep plants in the optimal growing conditions that cause undue stress and weaken the plant. For detailed Plant Care Checkout our Plant Care Tab.
• Disinfect recycled planters sufficiently to avoid transferring eggs or nymphs.
• Monitor plants regularly.
• Wipe down your foliage and stems often with a Neem Oil based pesticide.

For more on Plant Care Troubleshooting, Checkout our 2-Step Plant Health Guide.

Shop Pesticides in our Plant Care Section here.